Omission of definite article with musical instruments

I heard somewhere that if the instrument is big and can hardly or even can't be carried (like cello, piano, drum set, harp, grand-piano, organ, etc.) the definite article is needed. I am not sure if that's correct, though.

I remember when I first moved from the UK to the US, I was quite taken aback by the “I play piano” usage, without the article. So I’m pretty sure that this usage is very uncommon in the UK (at least among classical music circles). In US usage, Robusto’s answer, that the article-less usage is more common in reference to playing with a particular group, fits my experience (classical groups, north-east US) pretty well.

Articles are creatures more of usage and discourse than of grammar. The human speech communities involved (UK vs US; musicians, cooks, scientists, etc.) have certain patterns and expectations for use in the domains they control. The surrounding text (conversation or writing) also guides usage.
As an American, I accept using or omitting the article before an instrument; they are nearly interchangeable for me. I like the idea above that the article-less usage stresses playing with a group and the article usage stresses the position within the group. As an ESL teacher, I have generally taught that omitting the article highlights the action or activity, almost as if practicing-violin were a single intransitive concept, like swimming. Using the article gives a subtle shift in focus to the instrument. The following is a sentence I would be likely to produce; I would accept any version of this (article-wise) that I might hear: "When he was little he played violin, but he switched to the cello when he got to middle school."

I play piano??

This is I understand an American usage and is unacceptable in British or Australian English.

I play strings I play drums

This is the usual option to omit the (indefinite) article - it means you play instruments in this category but doesn't mean you play all stringed instruments (or whatever), but that you play some (and the implication is a few). The drums is a bit of a special case plural representing a singular set of drums or a number of different percussion instruments. If you play a number of different percussion instruments in an orchestra you would normally play drums and other percussion instruments and refer to percussion. The drum set in a band (which also includes non-drum percussion components - big hat, cymbals, etc.) is actually a stand in for the whole percussion section in a full orchestra, so the "role" usage I suggest below prevails.

I play percussion I play woodwind I play brass These are actually an adjective with an implicit "instruments" omitted, so it looks like a mass noun and doesn't have plural -s, but otherwise acts like the "strings" case above.

I'm intrigued by the @brilliant idea that it has to do with being portable.

I think the indefinite usage has more to do with playing a particular role in an ensemble or orchestra where there are multiple instruments playing the X part (implicitly plural even if singular in form), rather than a unique role (so definite singular). Thus it is appropriate to say I play X (meaning the role and the part as well as the instrument). These is confirmed by it being easier to omit the article when the "in the orchestra" or similar is explicitly or implicitly present.

I can say

I play cello I play trombone I play guitar I play banjo

I can't say I play piano?? I play mandolin?? I play harp??

The mandolin is portable. But there are not often multiple of any of these in a typical modern band, ensemble or orchestra. Piano and harp fit both theories.

I actually play the mandolin in a group and it is a small light instrument that can be very easily carried in a small case, more easily than a guitar so this argument is not good enough. I agree that "I play mandolin" seems to be a modern way of saying "I play the part devoted to the mandolin in this group". "I play the mandolin" is the best way to specify which instrument I play and the normal classical English usage.

"I shoulde'v learned to play the guitar, I shoulde'v learned to play them drums" - Dire Straits.

I would definitely go for "the piano". In fact the first sentence sounds strange.

Difficult to give basic rules. One idiomatic use with the definite article is

• I'm learning to play the piano. Longman DCE.

"I play piano" could easily be confused with "I play softly" as in music vocabulary piano means "The sound level when music is played softly". Maybe in this case adding the article "I play the piano" could sound more precise?

Here is an Ngram chart comparing the frequency of occurrence in published works of the phrases "played piano" (blue line), "played the piano" (red line) and "played a piano" (green line) for the period 175–2019:

The chart indicates that none of the three wordings were especially frequent until the early 1800s, at which point "played the piano" began a steady 120-year ascent, followed by a 30-year dip, followed by another period of increased frequency. For its part, "played piano" became increasingly (although somewhat irregularly) more frequent over the course of the twentieth century, after registering a low frequency throughout the nineteenth century.

The earliest Google Books matches for "played piano" involve instances where the phrase is not equivalent in meaning to "played the piano." For example, from "State of Music on the Continent," in The Quarterly Musical Magazine and Review (Autumn 1823):

March, 1823. On the 20 there was a concert for LEOPOLDINA BLAHETHA, 12 years of age, who played piano variations with orchestral accompaniments, composed by herself. This child merited and received (as usual) much applause.

Here, "played piano" is part of a longer phrase, "played piano variations"—that is "played variations on [the] piano." Elsewhere in this volume, a writer describes a child who "played the piano forte," and the periodical's usual wording for the instrument is "the piano forte," occasionally reduced to "the piano."

And from John Murray, Tour in Holland in the Year 1819 (1824):

The tones of the organ are very powerful, and when played piano very sweet, but the sound of that at Trent seemed to me, on recollection, to be preferable.

Here, the meaning of piano is "softly" (a complication of "play piano" noted in gabriellapax's answer). Multiple early Google Books matches for "played piano" have this meaning.

The earliest instance I've been able to find in which "played piano" carries the same meaning as "played the piano" is from a note dated March 26, 1843, in "Henri Heine About Music and Musicians," in The Music World (August 7, 1858):

The acquisition of Herr Pixis must have been some compensation to the French. He played piano, composed, too, very neatly, and his little musical pieces were particularly valued by the bird-sellers, who teach canary-birds to sing on hand-organs.

The phrase "played the piano," meanwhile seems to have been firmly established by the early decades of the 1800s. For example, from "Miss Paton," in Pocket Magazine (November 1822):

When only two years old she could name any tone, or semitone, on hearing it sounded—which was frequently ascertained by musical professors at the time. When four years of age, she played the piano, and a small harp, and also sung not only with some execution, but with a style peculiar to herself.

Over the past century, "played piano" and "played the piano" appear most frequently in situations where they could be used interchangeably. For example, from Julie Coryell & Laura Friedman, Jazz-Rock Fusion: The People, the Music (2000):

Miles, the son of Miles Dewey Davis II, a successful dentist and dental surgeon, and a mother who played piano and violin, moved with his family to St. Louis when he was one. Miles's father was a landowner as was his father before him.

And from Julie Coryell & Laura Friedman, Jazz-Rock Fusion: The People, the Music (2000):

I started playing the guitar when I was twenty. I was in college studying psychology and I suddenly realized that the guitar was my instrument and that I wanted to play, so I got a teacher and changed my major to music. I played the piano when I was five, hating every minute of it.

There are certainly some instances where "played the piano" refers to playing a particular piano that has been identified earlier in the same text. That may be what is going on here (from the same book):

There was music in the house all day. I had a sister who played classical piano and sang spirituals. My mother played the piano by ear and I had a brother who played the bass and tenor.

and here (same book again):

I began my involvement with music when I was seven years old by learning to play piano. This was at the encouragement of my mother who also played the piano, and I learned to play piano and learned music theory.

For the most part, however, in present-day English, "played the piano" means "played a type of musical instrument called a piano"—as does "played piano."