But honestly, there is an expectation of some level of competency/knowledge when trying to "claim" a hobby, because people consider a hobby as something you involve yourself in at more than a surface level.
Would you call yourself a polyglot because you know how to say "I love you." in eight different languages? Would you expect others to consider you multilingual? Probably not... There is some floor level of expectation before people would say you can "speak" a language and would consider you multilingual and a single phrase doesn't cut it for most people.
If someone tells me that they like to play a musical instrument - I'd first gauge their level of ability "What songs do you like to play?" followed by their knowledge of music theory "Could you show me a `Gm sus4 7` chord in the second inversion?" or a more basic "What are the 12 notes in Standard Western notation?"