Final answer:
Genes are most likely to influence expressive language. Research on the FOXP2 gene has shown that mutations in this gene can lead to speech and language disorders.
Step-by-step explanation:
The type of language that genes are most likely to influence is expressive language. Expressive language refers to the ability to produce words and sentences to communicate thoughts and ideas.
Research on a gene called FOXP2 has shown that mutations in this gene can lead to speech and language disorders. This gene is often referred to as 'the language gene' because it is believed to play a role in the development of language in humans.
For example, a study on a family in West London found that a genetic mutation on chromosome number 7, specifically on the FOXP2 gene, was associated with speech disorders and limited vocabulary.