The role of distributional factors in learning and generalising affixal plural inflection: An artificial language study

<p>Inflectional morphology has been intensively studied as a model of language productivity. However, little is known about how properties of the input affect the emergence of productive affixation. We examined effects of three factors on the learning and generalisation of plural suffixation by adults in an artificial language: affix type frequency (the number of words receiving an affix), affix predictability (based on phonological cues in the stem), and diversity (the number of distinct phonological cues predicting an affix). Higher type frequency and predictability facilitated the acquisition of trained inflections. Type frequency contributed to participants’ inflections of untrained words early during learning, while reliance on diversity emerged gradually, alongside knowledge of phonological cues. Diversity as well as type frequency contributed to the emergence of default-like inflections, including minority defaults. The results elucidate the role of affix diversity and its interaction with other factors in the emergence of productive linguistic processes.</p

Computer-based game board.

<p>Game tokens are represented by visual symbols, which correspond to nouns in Brocanto2. The tokens can further be distinguished by their background shape–square or round–each of which corresponds to a Brocanto2 adjective. Players can move, swap, capture, and release tokens, with each of these actions corresponding to Brocanto2 verbs, as well as move them either horizontally or vertically (corresponding to Brocanto2 adverbs).</p

Behavioral results.

<p>Mean <i>d′</i> scores and standard errors for the explicitly trained and implicitly trained subject groups at end of training and at retention.</p

Nonverbal subtask performance by Group (SLI vs. TD) and Real/Novel, showing mean <i>d</i>’ scores and standard errors.

<p>Nonverbal subtask performance by Group (SLI vs. TD) and Real/Novel, showing mean <i>d</i>’ scores and standard errors.</p

Example correct and word order violation Brocanto2 sentences.

<p> <i>Note:</i></p><p>* = violation.</p

ERP results.

<p>Voltage maps and waveforms reflecting the difference between violation sentence and correct sentence grand average ERPs by test session (end of training, retention) and group (explicit, implicit). Significant effects are indicated by letter on the voltage maps. Note that effects (a) through (f) parallel effects (a) through (f) in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032974#s4" target="_blank">Discussion</a> section “ERPs were more native-like at retention than at end of training”. (a) Left anterior-central negativity in the 300–500 ms time window found only at retention in the implicit group. (b) Anterior negativity found over both groups in the 500–700 ms time window only at retention. (c) Anterior negativity found over both groups in both test sessions in the 700–900 ms time window, but which was more robust at retention than at end of training. (d) Posterior positivity found over both groups and both test sessions in the 700–900 ms and 900–1200 ms time windows, but which was more robust at posterior sites at retention than at end training. (e) Right anterior positivity found in the 300–500 ms time window only in the explicit group at end of training. (f) Posterior negativity found over both groups in the 300–500 ms time window only at end of training. (g) Anterior negativity found over both groups and both test sessions in the 900–1200 ms time window.</p

Example stimuli from the nonverbal subtask (real and made-up objects) and the verbal subtask (real and made-up words).

<p>Example stimuli from the nonverbal subtask (real and made-up objects) and the verbal subtask (real and made-up words).</p

Recognition and retention accuracy for nonverbal information.

<p>Recognition and retention accuracy for nonverbal information.</p

Examples of the real and made-up objects used as stimulus materials.

<p>Examples of the real and made-up objects used as stimulus materials.</p

Adjusted means and standard errors for children with developmental dyslexia (DD) and typically developing control children (TD).

<p>Adjusted means and standard errors for children with developmental dyslexia (DD) and typically developing control children (TD).</p