Understanding Spanish Grammatical Development in Bilingual Children: What SLPs Need to Know
Background
Spanish–English bilingual children represent a large and growing population in the U.S. Yet, much of what we know about grammar development comes from monolingual norms. For bilingual children, language exposure and dominance shift over time, making development less predictable. Clinicians need research-based guidance to distinguish between typical bilingual development and language impairment.
Research Question
This study (Baron, Bedore, Peña, et al., 2018) asked:
Does accuracy of Spanish grammatical morphemes increase as children’s mean length of utterance in words (MLUw) increases?
Are there differences in the relative difficulty of grammatical morphemes depending on whether children are Spanish-dominant or English-dominant?
Study Design
Participants: 228 typically developing Spanish–English bilingual children, ages 4;0–7;6.
Measures: Accuracy on Spanish grammatical morphemes (plurals, articles, preterite, imperfect, prepositions, direct object clitics, subjunctive, conjunctions). MLUw was calculated from narrative samples.
Groups: Children were categorized as Spanish-dominant or English-dominant based on language input/output data.
Results
Highlights
MLUw, not age, predicted accuracy. Children with longer utterances produced morphemes more accurately. Age alone was not a reliable indicator.
Relative difficulty of forms was consistent across dominance groups:
Easiest: Imperfect, plural nouns, singular articles, conjunctions.
Moderate difficulty: Plural articles, preterite tense.
Most difficult: Prepositions, direct object clitics, subjunctive.
Spanish-dominant children outperformed English-dominant peers, but both groups followed the same order of difficulty.
Limitations
Data came from elicitation and sentence repetition tasks, not spontaneous language samples. This may underestimate accuracy in natural contexts.
Some MLUw ranges had small sample sizes, limiting stability of results.
The study did not break down subtypes of morphemes which could provide more nuanced findings.
Clinical Takeaways
Use MLUw over age to benchmark grammatical development in bilinguals.
Expect variability. Some forms (prepositions, subjunctive, direct object clitics) may remain challenging even after age 7.
Apply bilingual norms. Comparing bilinguals to English-only or Spanish-only expectations risks misdiagnosis.
Gather detailed language input/output data. This helps determine which language offers the most informative assessment context. Spanish-dominant and English-dominant children share the same developmental sequence, but accuracy differs by exposure.
