Learn Spanish (Latin America): Ellas son estadounidenses, pero hablan español. - They are American, but they speak Spanish.

Son comes from the verb ser (to be). In Spanish, we use ser to talk about identity and permanent traits, like someone's nationality or where they are from. We use estar for temporary states or locations, like how someone is feeling or where they are standing.

Since Ellas is feminine, why doesn't the word for American end in "-as" (like estadounidensas)?

Most Spanish adjectives change their ending to -o or -a to match the gender of the people you are talking about. However, adjectives that end in -e, like estadounidense, are neutral. They stay exactly the same for both masculine and feminine groups. To make it plural for Ellas, you just add an -s to get estadounidenses.

Why isn't the word español capitalized?

In English, we always capitalize the names of languages and nationalities (like Spanish or American). In Spanish, languages, nationalities, and days of the week are written in lowercase unless they are the very first word of a sentence.

Why is there no word for "they" right before hablan?