1. I can play the piano.
This is the standard and most commonly used form in both British and American English. It uses the definite article ("the") with a singular noun ("piano") to refer to playing the instrument in general. You’re not talking about a specific piano, but the ability to play that type of instrument. This construction applies to many musical instruments:
"I can play the violin."
"She can play the guitar."
2. I can play pianos.
This sentence is grammatically correct, but it has a different meaning. It suggests that you can play multiple pianos—either simultaneously (which is rare but not impossible) or individually. This phrasing might be used in a more specific context, such as:
"I can play pianos, but I prefer organs."
"I can play pianos in a showroom to demonstrate their sound."
In casual conversation, though, this sentence sounds unusual because people usually talk about their skill with a musical instrument in general terms, not the plural form.
Why Sentence 2 May Be Considered Acceptable in U.S. English
In informal or less standard usage, Americans sometimes drop "the" when talking about playing musical instruments. For example:
"I can play piano."
This is fairly common and understood in the U.S., but the plural ("pianos") is rarely used unless you're deliberately emphasizing multiple instruments.
Conclusion
Sentence 1 is the preferred and widely accepted form. Sentence 2 is grammatically correct but contextually unusual unless you're specifically referring to playing multiple pianos.
Let me know if you'd like further clarification! 😊