In the United States, Spanish-English bilingual children with speech sound disorders do not have equitable
access to the efficient treatment options currently available for their monolingual English-speaking peers. This
is a significant barrier to optimal outcomes for a large and underserved population in this country, considering
that nearly 1 in 4 children in the US lives in a household where a language other than English is spoken. When
children enter kindergarten with delayed speech development, they are more likely to struggle with language,
reading, and academic achievement. This can have long-term effects on their psychosocial well-being and
future employment outcomes. By improving the efficiency of treatment for speech sound disorders, we have
the potential to greatly improve outcomes for these children and also reduce strain on healthcare and special
education resources. Previous studies have shown that teaching English-speaking children more difficult
speech sounds, like consonant sequences, such as "fr" in "free," leads to broader improvements in their
speech. They not only learn the targeted sounds but also simpler sounds like "ch," "th," "v," "g," and "k." This
suggests that teaching more complex sounds can have an efficient impact on the entire sound system, even
on sounds that were not directly practiced. However, in order to apply this approach to Spanish-English
bilingual children, we must answer two important questions. First, we need to determine if teaching complex
sounds results in similar overall improvements in speech when bilingual children receive treatment in either
Spanish or English. Second, because bilingual children are simultaneously developing two languages, we
need to understand if teaching more complex speech sounds in one language has a broader impact, not only
on the targeted language but also on the untreated language. To address these questions, we will conduct a
Phase I Clinical Trial using single-subject experimental design with a) complex and b) simple treatment
conditions. This design allows us to observe, for bilingual speech treatment, the extent of system-wide
improvement and across-language transfer resulting from complex treatment targets. The treatment will be
provided in Spanish (Aim 1) and English (Aim 2). In Aim 3, we will analyze the data gathered from Aims 1 and
2 to explore how specific Spanish or English sounds interact with different treatment targets. This analysis will
help us to understand the mechanisms of broad phonological change across different languages. The
implications for this research are potentially far-reaching. By uncovering the cross-linguistic mechanisms
involved in broad-based phonological learning, we can better understand how complexity influences the
transfer of skills across languages. This research would establish a foundation from which to develop more
efficient and equitable speech treatment procedures that are appropriate for monolingual and bilingual children,
thereby better meeting the needs of the increasingly diverse population with speech sound disorders.