It is well known that different languages have different phonological structures. Some have lots of sounds put together in certain ways, other languages have fewer sounds and these go together perhaps in other ways. Comparing Spanish and English is interesting in the US context because Spanish is the second most common language after English. The majority of English language learners in the US speak Spanish as a first language. What do we know about the phonological structures of each language? Spanish has a 5 vowel system, English has 14. Spanish has 18 English has 24. Spanish has longer words; English tends to have shorter words. You can read more about the sounds of each language and their comparisons in work by Leah Fabiano-Smith, Brian Goldstein, and Christina Gildersleeve.
Anyway, we were interested in whether children with different levels of experience in Spanish and English would perform differently on Spanish vs. English nonwords. We used two sets of nonwords, both developed in the same way (see Dollaghan & Campbell). Sounds were those that are acquired early, and combinations that occur in real words, but none of the individual syllables were those that DO occur in real words. So, in that respect the nonwords were nonwordlike (there are wordlike nonwords– these might for example rhyme with real words).
In this study, We had 26 Spanish dominant children and 26 English dominant children, they were all in kindergarten. We matched on age in months and inverse matched on percent exposure in English and Spanish. They were also matched on when they first started learning English. So, a child who started learning English at age 3, with a 75% exposure to English was matched with a same age child who started learning English at age 3 and had 75% exposure in Spanish). All children had nonverbal IQs in the normal range and a standard score of 80 or higher on the Bilingual English Spanish Assessment in their better language.
Results were interesting and to a certain extent surprising. The Spanish-dominant children as a group performed better on the nonwords in BOTH languages compared to the English-dominant children. The Spanish nonwords were easier for both groups of children.
So, why might Spanish dominant bilingual children show an advantage for nonwords regardless of language in comparison to English dominant bilingual children? One possibility is that more practice with Spanish– which has longer words than English gave Spanish dominant children an advantage on the longer words overall. This idea is consistent with other studies of nonword repetition of children who speak languages that have lots of long words (like Greek). It could be that the Spanish dominant children were able to process the Spanish words more automatically because they had longer experience with Spanish. Even though the English dominant children had more current English exposure, recall that they were matched on age of first English exposure, so perhaps neither English nor Spanish was completely automatic for them and they had to use more cognitive resources to hear and remember the words as they got longer.
Although we don’t have enough evidence to know–I wonder if this also gives us a glimpse of the advantages that children gain from establishing a firmer foundation in their L1 before shifting into L2 completely.