Integrating Regular and Irregular Forms

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PIs Nora Presson, Brian MacWhinney, Nuria Sagarra
Faculty MacWhinney
Postdocs n/a
Others with > 160 hours n/a
Study Start Date 09/10
Study End Date 12/10
Learnlab n/a
Number of participants (total)
Number of participants (treatment)
Total Participant Hours


Following the initial study of Spanish students practicing with irregular verbs (Rules_vs._Analogy_in_Spanish_Irregular_Verbs), we use a similar practice activity that adds regular verbs (in addition to those inflectional forms of irregular verbs that follow the regular pattern).


Research question

There are two major methodological changes from the first study. First, we implement as between- instead of within-subjects the instructional manipulation, whether incorrect feedback is presented as a rule for when stem transformations are appropriate or presented as the correct answer with a correct and analogous high-frequency exemplar to model.

Second, we are interested in how regular forms of verbs that sometimes require transformations on the stem (i.e., regular forms of "irregular" verbs) differ from forms where the verb is regular (i.e., no forms require a transformation). It is possible that the structure of the first experiment, presenting only verbs that do require a transformation, led to an expectation of irregularity, which would explain how some groups declined in accuracy on the regular forms of those irregular verbs (although not by much) after training.

Background and significance

Learners have difficulty processing inflected verb forms (Clahsen & Felser, 2006; Johnson & Newport, 1989). Some models of language processing postulate that this difficulty stems from learners' lack of ability to compose regular inflected forms as native speakers can (e.g., the Declarative/Procedural model of Ullman, 1997; 2001). This prediction stems on the assumptions that:

  • native speakers store irregular forms but compose (some but not necessarily all) regular ones (see for example Pinker, 1997)
  • learners are unable to process (decompose) morphologically complex forms in a nativelike way (possibly because of a Critical Period effect)

The evidence that learners treat regulars and irregulars similarly (from which most infer that both are stored) comes from priming studies, where native speakers show priming of the base stem for regular but not irregular inflections, and also from production data showing frequency effects on latency for irregular but not regular inflected forms.

However, most previous studies of the difference between regular and irregular forms do not distinguish between levels or types of irregularity. There are irregular forms that have predictable changes, and inflected forms that do not show any idiosyncratic transformation, though other forms of the same verb do.

One level of distinction comes from a recent study by Bowden and colleagues (2010) that compared Spanish -ar verbs, which are the most frequent type of verbs, are most often regular, and encompass most novel words, to -er and -ir verbs, which have fewer types and are more likely to be irregular. They showed that native speakers only failed to show frequency effects when producing -ar but not -er/-ir regular inflected forms in both present (irregularities possible) and imperfect (almost no possible irregularities) tenses. Also, learners showed frequency effects (which they interpret to mean forms are stored and not composed) for all types of verbs and tenses.

Most of the "irregular" verbs used in that study, however, do show predictable patterns that can explain the stem transformations. We are interested in whether these regularities matter; that is, whether a wholly idiosyncratic transformation is really processed the same way as an irregular that follows a predictable pattern.

We compare two types of irregularity: first, spelling change verbs, where a change is needed to preserve the phonological form of the verb (e.g., sacar "to take out" -> saqué "I took out" because the regular transformation would lead to sacé, with a soft 'c'.). We compared those to stem change verbs, where the change is not meant to preserve phonology but does follow a similar pattern across a large number of verbs. Also, we compare irregular verbs to regular verbs, where no forms require any transformation of the stem.

Learner performance is full of errors, so we are interested in how to improve performance with practice and explicit feedback. In this study, we used two feedback types: an explicit explanation of when to transform the verb stem (i.e., which forms are irregular), and presenting a correctly inflected form of a highly frequent verb their teacher judged that they would know. These were assigned between subjects.

Dependent variables

  • Response accuracy
  • Latency of correct responses

Independent variables





Annotated bibliography