* Definition of "speak English": What constitutes "speaking English"? Fluency? Comprehension? Basic understanding? The definition significantly impacts the percentage.
* Data limitations: There isn't a reliable census or survey that specifically asks about English proficiency.
* Immigration and language diversity: The U.S. has a diverse population with various native languages. Many Americans are bilingual or multilingual.
However, we can look at some general trends:
* English as the dominant language: English is the official language of the U.S., and it's the primary language spoken by a vast majority of Americans.
* Linguistic minorities: There are significant communities that speak languages other than English at home. This is especially true in major cities and certain regions.
* High English proficiency: Studies suggest that a very high percentage of Americans have a good command of English.
Instead of a precise percentage, it's more accurate to say that English is the dominant language spoken by a vast majority of Americans.