*3.2. Results*

**Picture-naming task.** The CTSL-1 signers produced a total of 70 sign strings involving a total of 129 signs in all strings. The CTSL-2 signers produced 68 sign strings involving a total 163 signs in all strings (repetitions excluded). The overall most frequent strings were two-sign strings (41.3%, e.g., BOTTLE, WASHING BASIN, and GLASS), followed by single signs (31.1%, e.g., BOOK, BOX, and GLASSES) and three-sign (16.6%, e.g., TEAPOT and TOY CAR) and four-sign or more strings (10.9%, e.g., SUITCASE). This was a slightly different pattern from that in study 1, in which the frequency of single signs was higher than that for the two-sign strings. However, a similar pattern to the one in study 1 in the distribution of sign strings was observed: the CTSL-1 signers used significantly shorter strings of signs (*M*CTSL-1 = 1.88, *SD*CTSL-1 = 0.64) than the CTSL-2 signers (*M*CTSL-2 = 2.37, *SD*CTSL-2 = 0.59) (*t*(15) = 2.131, *p* = 0.03). In addition, the CTSL-1 signers produced significantly more single-sign strings than the CTSL-2 signers (χ2(1) = 6.93, *p* = 0.0085) (Figure 7).

**Figure 7.** Distribution of sign strings. The *Y*-axis represents the proportional frequency of responses involving sign strings on the *X*-axis. The blue bars represent CTSL-1, and the orange bars represent CTSL-2 (Ntotal = 138, NCTSL-1 = 70, NCTSL-2 = 68). CTSL-1 produces significantly more single-sign strings than CTSL-2.

As in study 1, there were no significant differences in the implementation of the iconic strategies across cohorts. In the overall sign strings (Ntotal = 292), the primary strategy was *object* (42%, 8 of instances), followed by the *action* (26.7%), simultaneous production of *action* and *object* (20.9%), and *deictic* (6.8%) strategies. This was a slightly different pattern

than the one in study 1, in which *action* was favored over *object* as the primary strategy. DRESS, GLASS, GLASSES, and HAT frequently elicited object-based strategies, while BOX, PLASTIC BAG, WASHING BASIN, and SUITCASE frequently elicited action-based strategies combined with object ones or simultaneous use of action and object strategies.

In two-sign strings, a pattern similar to that in Study 1 was observed. The most common combination was *action—object*, followed by *object—action* and *object*, and *action— action* combinations (see Figures 8 and 9). BALL, DRESS, PLASTIC BAG, WASHING BASIN, SCARF, WATER BOTTLE, and GLASS frequently elicited two-sign (or more) strings.

**Figure 8.** Combination of strategies used in two-sign strings. The *Y*-axis represents the proportional frequency of responses involving the combination of iconic representations on the *X*-axis (Ntotal = 57, 41.3% of all strings). The categories represent the constituents irrespective of their order (i.e., the bar for act + object also includes object + act combinations).

**Figure 9.** (**a**) Stimulus item used in the task. (**b**) Reenactment of washing (*action*). (**c**) Tracing of the circular shape (*object*). The *action*-*object* combination depicted in (**<sup>a</sup>**,**b**) refers to a WASHING BASIN.

**Communicative task.** The CTSL-1 signers produced a total of 84 sign strings involving a total of 101 signs in all strings. The CTSL-2 signers produced 111 sign strings involving a total 151 signs in all strings (repetitions excluded). The results show that an overwhelming majority of the overall productions in context were single signs (74.8%, e.g., GLASSES, HAT, JACKET, and BOOK), followed by two-sign strings (21%, e.g., PLASTIC BAG and WASHING BASIN) and three-sign strings (4.1%, e.g., SUITCASE and TOY CAR). Both the CTSL-1 and CTSL-2 signers used significantly shorter strings when the target objects (Tables 2 and 3) were presented in context as opposed to being presented in isolation (CTSL-1: *t*(15) = 2.131, *p* = 0.001; CTSL-2: *t*(15) = 2.131, *p* < 0.001). Figure 10 shows that

single-sign responses were a lot more frequent in context (χ2(1) = 62.71, *p* < 0.0001). Furthermore, responses involving two or three signs were significantly less frequent when the objects were presented in context (two-sign strings in context vs. in isolation (χ2(1) = 15.93, *p* = 0.0001) and three-sign strings in context vs. in isolation (χ2(1) = 15.08, *p* = 0.0001)). Multi-sign strings involving four or more signs were not produced in context (i.e., the signers tended to produce short labels for objects when they were presented in context, rather than producing longer descriptions as they did when they were presented in isolation).

**Figure 10.** Sign strings produced for objects when they were presented in context vs. in isolation. The *Y*-axis represents the proportional frequency of sign strings on the *X*-axis. The blue bars represent responses produced for objects presented in context, and the orange bars represent responses produced for objects presented in isolation (Ncontext = 195, Nisolation = 138). CTSL-2 produces significantly longer sign strings than CTSL-1.

While there was a significant difference between the lengths of the responses for the CTSL-1 and CTSL-2 signers when objects were presented in isolation, there was no overall significant difference across cohorts when the same objects were presented in context (*M*CTSL-1 = 1.23, *SD*CTSL-1 = 0.27; *M*CTSL-2 = 1.39, *SD*CTSL-2 = 0.32; *t*(15) = 2.131, *p* = 0.12). Although the general tendency of both cohorts was to produce shorter responses in context with no overall significant difference in the lengths of the sign strings across cohorts, CTSL-1 still produced more single signs in context (χ2(1) = 5.55, *p* = 0.018), and CTSL-2 produced more two-sign strings (χ2(1) = 5.63, *p* = 0.0176), indicating more reliance on combinatorial responses to label objects not only in isolation but also in context (Figure 11). Items which were not always labeled with a single sign and still produced in combination with at least one more sign in context were PLASTIC BAG, TEAPOT, DRESS, BOTTLE, WASHING BASIN, TOY CAR, STICK, SUITCASE, and GLASS.

Overall, for the sign strings produced in context by both cohorts (Ntotal = 252), the primary strategy was *object* (53.1% of instances), followed by simultaneous production of *action* and *object* (30.1%), *action* (10.7%), and *deictic* (5.9%) strategies. As in the responses for the target items elicited in isolation, there was no significant difference across cohorts in the implementation of iconic strategies either. However, there were significant differences in the implementation of iconic strategies when the target objects were presented in isolation vs. context: action-based iconic representations were produced significantly less in context (χ2(1) = 22.2, *p* < 0.0001), and object-based and simultaneous action and object strategies were used significantly more (χ2(1) = 5.73, *p* = 0.0167 and χ2(1) = 6.08, *p* = 0.0137, respectively). Many objects involved an *action* component in response to objects presented in isolation (e.g., BALL, BOX, JACKET, PLASTIC BAG, WASHING BASIN,

SCARF, SUITCASE, TEAPOT, TOY CAR, and WATER BOTTLE) (Figure 12), whereas fewer objects involved an *action* component in response to an object presented in context (e.g., BALL, JACKET, PLASTIC BAG, SUITCASE, and TOY CAR) (Figure 13).

**Figure 11.** Sign strings produced by CTSL-1 and CTSL-2 for objects when they were presented in context. The *Y*-axis represents the proportional frequency of sign strings on the *X*-axis. The blue bars represent responses by CTSL-1, and the orange bars represent responses by CTSL-2 (NCTSL-1t = 84, NCTSL-2 = 111). CTSL-2 produces significantly longer sign strings than CTSL-1.

**Figure 12.** Iconic strategies by item when objects were presented in isolation. The *Y*-axis represents the number of occurrences of iconic strategies used in items on the *X*-axis (Nisolation = 292).

Some of the actual responses to the stimuli as they were produced by CTSL-1 signers in isolation vs. context were as follows:

#### (1) **STICK** [=FIRE ˆ CUT ˆ SIZE]<sup>8</sup>

In (1), STICK, as produced in isolation by a CTSL-1 signer, was a three-sign string. The first sign had an action-based iconic form resembling blowing, which represents FIRE in CTSL (Figure 14b). This was followed by a simultaneous action and object sign for CUTTING, representing cutting wood. Both hands are flat in a cross-configuration, with the non-dominant hand standing still and the dominant hand making a repetitive downward and upward movement on the non-dominant hand (Figure 14c). The last component of the string was an object-based iconic sign depicting the size of the target object with both hands flat facing each other on a horizontal plane (Figure 14d). In sum, this is an object with a certain size that is cut and used for making fire.

#### (2) **STICK** [= FIRE ˆ CUT] BREAK WOMAN BREAK

*Eng*. "Woman breaks or is trying to break the stick."

In (2), the same participant dropped the last component denoting the size of the object and produced a two-sign string for STICK in context (Figure 14b,c).

**Figure 14.** (**a**) STICK produced in isolation by a CTSL-1 signer. (**b**) FIRE. (**c**) Action of CUTTING. (**d**) Size of the target object. All three together refer to the target object. For STICK in context, the first two components were preserved (**b**,**<sup>c</sup>**), and the last component depicting the size of the object (**d**) was dropped.

#### (3) **BALL** [= CIRCULAR SHAPE ˆ BALL THROW]

In (3), another CTSL-1 signer produced BALL as a two-sign string in isolation. The first sign in the string denotes the circular shape of the object with both hands (Figure 15b). The second sign is a simultaneous combination of the same iconic form with a repetitive forward and backward ball-throwing action in front of the body (Figure 15c).

**Figure 15.** (**a**) BALL produced in isolation by a CTSL-1 signer. (**b**) The circular shape of the object, and (**c**) depicts the simultaneous object and action of BALL THROWING. Together, they refer to the target object. For BALL in context, the first component (**b**) was preserved, and the second component (**c**) was dropped.

#### (4) **PLASTIC BAG** [= HOLD ˆ SPHERICAL SHAPE]

In (4), the same CTSL-1 signer produced PLASTIC-BAG in isolation as a compound involving the action of HOLDING with both hands on both sides of the target object (Figure 16b), followed by a two-handed sign depicting the size and spherical shape of the object (Figure 16c).

#### (5) PUT INSIDE WOMAN **BALL**[= CIRCULAR SHAPE] PUT INSIDE **PLASTIC BAG**[= HOLD] PUT INSIDE

*Eng*. "Woman puts the ball inside the plastic bag."

In (5), the CTSL-1 signer produced a reduced form for both BALL and PLASTIC BAG in context. The component containing the size and shape information of BALL was preserved, but the one containing an associated action was dropped. For PLASTIC BAG, the component denoting the action of HOLDING was preserved, and it was produced as a one-handed sign in context (Figure 16d), but the sign denoting the shape and size of the object was dropped (Figure 16c). In other words, there was no systematicity regarding which iconic form to preserve and which one to drop. In addition, further information regarding the physical form of BALL and PLASTIC BAG was incorporated into the main action: PUT INSIDE. The non-dominant hand represents a circular object with a container function (i.e., PLASTIC BAG), and the dominant hand represents another—the circular object (i.e., BALL)—and makes a movement toward the non-dominant hand to signal that the BALL goes into the PLASTIC BAG (Figure 16e).

**Figure 16.** (**a**) PLASTIC BAG produced in isolation by a CTSL-1 signer. (**b**) The action of HOLDING, and (**c**) depicts the spherical shape of the target object. Together, they refer to the target object. For PLASTIC BAG in context, (**d**) depicts the action of HOLDING, referring to the target object in a reduced form. (**e**) The action of PUTTING INSIDE, in which the reduced form of BALL and PLASTIC BAG are incorporated.

Some of the actual responses to the stimuli as they were produced by the CTSL-2 signers in isolation vs. context are as follows:

#### (6) **BALL** [= CIRCULAR SHAPE ˆ BOUNCE]

In (6), similar to the response of the CTSL-1 signer (Figure 15), the CTSL-2 signer produced a compound involving an object-based iconic form in response to the image of a BALL (Figure 17b). This was followed by a simultaneous object and action sign signaling the shape of the target object incorporated in a bouncing action (Figure 17c). However, the imagistic forms of the iconic strategies the CTSL-2 signer used differed from the ones the CTSL-1 signer used. The CTSL-2 signer produced a one-handed circular shape to represent a specific smaller bouncing BALL, as was displayed in the stimulus.

**Figure 17.** (**a**) BALL produced in isolation by a CTSL-2 signer. (**b**) Circular shape of the object. (**c**) Simultaneous object and action of BALL BOUNCING. Together, they refer to the target object. For BALL in context, the first component (**b**) was preserved, and the second component (**c**) was dropped.

#### (7) **PLASTIC BAG** [= HOLD ˆ PUT INSIDE ˆ SIZE]

In (7), the CTSL-2 signer produced a three-sign string to refer to PLASTIC BAG in isolation. The first sign refers to the action of HOLDING a bag (Figure 18b). The second sign is a simultaneous action and object of putting something inside a container, with the non-dominant hand representing the container and the dominant hand representing the agen<sup>t</sup> performing the action (Figure 18c). The third sign refers to the spherical shape and size of the target object, with two C-shaped hands facing each other on the horizontal plane (Figure 18d).

#### (8) WOMAN **PLASTIC BAG** [= PUT INSIDE ˆ HOLD ˆ SIZE] **BALL**[= CIRCULAR SHAPE] PUT INSIDE

*Eng*. "Woman puts the ball inside the plastic bag."

In (8), just as the CTSL-1 signer did, the CTSL-2 signer also dropped the second sign for BALL in context and produced only the first sign denoting the size and shape of the object. For PLASTIC BAG, the CTSL-2 signer kept all three signs of the sign string and produced all of them consistently in the same imagistic form (Figure 18b–d), but HOLD and PUT INSIDE came in varying orders. It is important to note that the first sign (i.e., PUT INSIDE) in the sign string referring to a component of PLASTIC BAG was different from the main action of the sentence (i.e., PUT INSIDE) in that it was smaller in form and involved only a brief movement of putting inside (Figure 18c). In contrast, PUT INSIDE as the main action of the sentence was bigger in form, with the movement of the dominant hand more emphasized and the function of the non-dominant hand as a container more visible (Figure 18e).

**Figure 18.** (**a**) PLASTIC BAG produced in isolation by a CTSL-2 signer. (**b**) Action of HOLDING. (**c**) The simultaneous action and object of PUT INSIDE. (**d**) Size and shape of the target object. All three together refer to the target object. For PLASTIC BAG in context, all three components were preservsed in context, but the first two components varied in order. (**e**) The main action for PUT INSIDE in the sentence, which is different in its form from the form of the PUT INSIDE sign in (**b**).

#### *3.3. Summary and Conclusions*

The goal of this study was to replicate the results from study 1 and investigate the lexical inventory of a newly emerging language when objects were presented in isolation vs. in context. In line with the findings from study 1, the CTSL-1 signers produced significantly shorter sign strings than the CTSL-2 signers when objects were presented in isolation. They also produced more single-sign strings than the CTSL-2 signers. There was no significant difference across cohorts in their implementation of iconic strategies in either study 1 or study 2. While the most frequent iconic strategy was *action* in the overall signs produced in study 1, it was the *object* strategy in study 2. In the two-sign strings, an *object* strategy was frequently combined with an *action* or a simultaneous *action* and *object* strategy. This pattern further corroborates the findings of the two-sign strings in study 1.

When objects were presented in context, the lengths of the strings overall were significantly shorter compared with the lengths of the strings elicited when objects were presented in isolation. This finding suggests that the signers gave longer descriptions for objects when they were presented in isolation rather than labeling them with a single sign, as they frequently did in context. In addition, no significant difference in the lengths of the sign strings across cohorts was found. Yet, the CTSL-1 signers still produced significantly more single-sign and significantly fewer combinatorial responses than the CTSL-2 signers. This shows that the CTSL-2 signers were not only more elaborate in giving descriptions for objects in isolation, but they were also more precise in disambiguating them with combinatorial structures in context. Finally, there was no difference either across cohorts in the implementation of iconic strategies or across the sign strings within both tasks. However, there were significant differences in the implementation of all iconic strategies across tasks. Fewer *action* strategies and more *object* and simultaneous *object* and *action* strategies were implemented when the target items were presented in context.

#### **4. General Discussion**

#### *4.1. Object-Based or Action-Based Iconic Strategies: Which One Is More Salient?*

One of the main goals in this study was to understand whether an imagistic *object* form, an *action* associated with the target object, or the simultaneous use of both is more salient to be selected for iconic representations of everyday objects. With this goal in mind, a set of everyday objects not previously studied for iconicity in CTSL was selected as the stimuli in study 1 and study 2. They were coded for iconic representations in five categories: *object*, *action*, simultaneous use of *object* and *action*, *deictic*, and *other*. Any iconic forms signaling the shape and size information either through a static phonological realization or tracing the shape of the target item were collapsed together under the object category, as they all referred to a physical feature of an object. In order to minimize a potential bias for certain iconic representations, semantic categories such as fruits and vegetables and tools were not used in the stimuli sets. In study 2, the target objects were presented with a

non-prototypical action (e.g., "hat" with "throw" or "glasses" with "drop") in context in order to prevent a potential bias for the simultaneous use of action and object strategies through object incorporations into prototypical actions.

Previous investigations on CTSL have revealed cross-linguistic similarities of iconic patterning in that CTSL uses more action-based iconic forms for tools, whereas more object-based iconic forms for semantic categories such as vegetables and fruits are used. Similar findings have been reported in the gestural productions of non-signers and signers of ASL, ABSL, ISL, German Sign Language (DGS), Japanese Sign Language (JSL) (Hwang et al. 2017), as well as San Juan Quiahije Chatino Sign Language (Hou 2018). Moreover, in line with the findings in ASL, NSL, and Nicaraguan homesign systems (Goldin-Meadow et al. 2015), CTSL signers have been shown to favor object-based strategies in non-agentive contexts and action-based strategies in agentive contexts (Ergin and Brentari 2017). In summation, CTSL typologically fit with the way other sign languages favor their use of iconic strategies in certain semantic categories and event structures.

When potential biases are removed, the available data in this study sugges<sup>t</sup> that there is not a strong preference in CTSL for either action-based or object-based iconic forms for referring to everyday objects, as study 1 presented evidence in favor of action-based strategies and study 2 presented evidence for object-based strategies. Action-based iconic representations have been claimed to be the building blocks of an emerging lexicon in the manual modality (e.g., Ortega et al. 2014 and Ortega and Özyürek 2020). In particular, Ortega and Özyürek (2020)<sup>9</sup> presented evidence for the overwhelming use of *acting* in gestures across a variety of concepts10. While study 1 presented evidence in line with this finding (i.e., action is the primary mode of iconic representation, closely followed by object-based strategies), study 2 portrayed another possibility where object representations dominate the cumulative results. In other words, there is no suggestive evidence from the present data for action-based iconic representations to be the main precursor of an emerging lexicon in the manual modality. Mental images capturing the physical form (i.e., size and shape) of the target items or the simultaneous selection of an image representing the physical form of an object and an action associated with that object seem to be equally likely to be selected for iconic representations.

#### *4.2. Is There a Difference across Cohorts of Signers in the Use of Iconic Strategies?*

Previous research on emerging sign languages presented evidence for developmental differences across cohorts of signers (e.g., Senghas et al. 2004 and Padden et al. 2013). For instance, Ergin and Brentari (2017) showed that CTSL in its first generation favored action-based iconic forms over object-based iconic forms and evolved into systems favoring the opposite patterns as of the second generation. NSL in its first generation favored objectbased strategies and evolved into a system favoring action-based iconic forms over time (Goldin-Meadow et al. 2015). Along these lines, previous research on CTSL also presented evidence for generational differences in various linguistic domains, such as systematic opposition in word order preferences across event types, the use of distinct morphological devices in differentiating various verb classes, and in modification strategies (Ergin et al. 2018, 2020; and Ergin et al. 2021, respectively). For example, in response to transitive constructions, CTSL-1 frequently produces object-verb (OV) sequences without the subject (S) and irrespective of the semantic structure of the construed event, whereas CTSL-2 produces more complete responsenses involving all three arguments, with a systematic opposition of SOV and OSV word orders in those events involving an inanimate patient acted upon by a human agen<sup>t</sup> and those involving a human patient acted upon by a human agent, respectively (Ergin et al. 2018). Similarly, CTSL-1 signers produce significantly shorter responses and make use of simple or complex modification structures significantly less often than CTSL-2 signers in reliably differentiating between the modifier and the modified (Ergin et al. 2021). This study reveals a similar developmental pattern across generations of signers: the CTSL-1 signers produced single-sign responses significantly more often than the CTSL-2 signers, and their responses in object descriptions were significantly shorter

both in study 1 and study 2. In other words, the CTSL-2 signers relied on more combinatorial sequences of signs, probably to mark the target objects more precisely. Regarding the preference for compositionality between CTSL-1 and CTSL-2, the findings of the current study can be considered evidence of a systematization of the lexicon, being more precise semantically and more complex morphologically.

For the implementation of iconic strategies, these data show that there were no differences across generations of signers. Many of the iconic forms were already present as of CTSL-1, and they did not wait until CTSL-2 to emerge. Similarly, Ergin et al. (2020) reported that *mirroring*, an *iconically motivated morphological device* that makes use of both hands in a mirror configuration to express symmetry and plays a differentiating role between events involving symmetry and asymmetry, is present both in CTSL-1 and CTSL-2 with no significant difference. Other devices that do not iconically represent a mental image, such as *temporal sequencing* of events (e.g., WOMAN PUSH and GIRL FALL for "Woman pushes girl"), follow a developmental path that requires them to be invented over time, as they are almost completely absent in CTSL-1 and start to emerge in CTSL-2. Although many linguistic devices may require a developmental trajectory across generations, iconic representations may not be one of them. This may be a reason for not observing differences between CTSL-1 and CTSL-2 in the implementation of iconic strategies in the lexicon.

#### *4.3. Is There a Difference in the Use of ˙ Iconic Strategies and Their Combinations When the Target Objects Are Presented in ˙ Isolation vs. Context?*

The available data in this study present evidence for significant differences in CTSL responses when objects are presented in isolation and in context. First, both cohorts produced significantly shorter responses in context. Second, there was no significant difference in the lengths of the responses between CTSL-1 and CTSL-2 in context. However, they significantly differed from each other in their responses when the objects were presented in isolation, and CTSL-2 still used more combinatorial forms in context, suggesting that CTSL-2 may be more reliably marking the target's real-world referents by narrowing the number of possibilities for the intended meaning.

Another key finding here is the differences in the implementation of iconic strategies in response to objects presented in isolation and in context. Both cohorts were inclined to use significantly fewer action-based iconic strategies in context and significantly more object-based or simultaneous object- and action-based strategies. When presented in isolation, in order to identify the target items more precisely, signers may tend to put them in context and produce iconic combinations involving actions associated with the target objects along with the object-based iconic forms. Alternatively, they may tend to incorporate the object-based forms into the associated actions and simultaneously produce both in order to reliably convey the intended message (e.g., see Section 3.2 for PLASTIC BAG and BALL being incorporated into the main action PUT INSIDE). However, when items are presented in context, this may not be considered a necessary condition, as there are already sufficient contextual clues contributing to the accurate interpretation of the event structure.

#### *4.4. Final Remarks and Future Directions*

In summation, this study adds to the body of research investigating how object-based and action-based iconic representations and their combinations are used for referring to everyday objects in the emerging lexicon of CTSL, which has emerged in the absence of a conventionalized linguistic system. It also expands the previous research on the similarities and differences across CTSL generations and items produced in isolation vs. in context. In order to talk about the CTSL lexicon as a whole and to generalize these results to natural discourse in CTSL, further evidence from the conversational data should be analyzed for future work.

**Supplementary Materials:** The following supporting information can be downloaded at https:// www.mdpi.com/article/10.3390/languages7020118/s1. Supplementary S1: the family tree. Supplementary S2: the pictures of the stimuli items. Supplementary S3: the images of the objects. Supplementary S4: a sample trial in the task.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** The study protocol was approved by the Institutional Review Board of Bo ˘gaziçi University Social Sciences Ethics Committee (SBINAREK) 2019-43.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** The author thanks Carol Padden and Deniz ˙Ilkba¸saran for their help with data collection for Study 1 in August 2013, and Ray Jackendoff and Anastasia Smirnova for their useful comments on the stimuli set in Study 2. The documentation of Central Taurus Sign Language was funded by Center for Cognitive Studies at Tufts University in 2013–2014, by Tufts Collaborates in 2015–2016 and it is currently funded by the Scientific and Technological Research Council of Turkey (Project no: 118C358).

**Conflicts of Interest:** The author declare no conflict of interest.
