Among all the mother-tongues that are spoken in the United States of America, Spanish is the most frequent.

The United States Census Bureau reported that in 2019 approximately 41 million individuals who spoke Spanish at home were aged 5 and higher, thus Spanish was the most commonly spoken non-English language among those in the country.
Other commonly spoken non-English languages in the United States include:

• Chinese: (the Chinese also include Cantonese, Mandarin, and others under this category in this context)
•  Tagalog (the language spoken in the Philippines).
• Vietnamese
• French
• Arabic

Also, most of these languages practically cannot reach the level of extension as Spanish does which is the often-used non-English language in the U.S.

People speaking other languages apart from Spanish been on the rise in the country which have seen keen inclusion of bilingual education, resources, and services in sectors such as government, health, and business to make it convenient of people who do not speak Spanish.

However, none of these languages come close to the prevalence of Spanish as the most widely spoken non-English language in the United States.
The widespread use of Spanish as a second language has led to increased efforts to provide bilingual education, resources, and services in various sectors, including government, healthcare, and business, to better serve the Spanish-speaking population in the country.