Wovon man nich sprechen kann, darüber muß man schweigen.
[What we cannot speak about we must pass over in silence.]
However, I believe it is important to read this text in the light of two other philosophers, one of whom preceded Wittgenstein and one of whom followed him. The predecessor is Plato on ground that I have visited many times concerned with the intimate relationship that exists between knowledge and description. The more recent philosopher is Richard Rorty, who talked about "keeping the conversation going" as a (if not the) major obligation of philosophy. Put another way, much (if not most) of what we know emerges from our "conversations" with others. This is true whatever we may "acquire" through our personal experiences; and it comes about through the extent to which we share those experiences. This reflects back on Plato to the extent that much of that sharing derives from our capacity to describe the experiences. Some of us can achieve such description through musical performances or "works of art" (as when Igor Stravinsky once told a television audience, "I don't want to tell you more, I only want to play you more"); but the rest of us all-too-humans usually cannot get at description by any means other than through our command of the language(s) we speak!
This raises at least a potential paradox of knowledge acquisition: Can that "local critic" in San Mateo ever get beyond passing over Messiaen in silence? To be even more reductive and trying to deftly avoid those who try to play Beethoven to a child still in the womb, we come into this world with no experience of having heard Messiaen (and, for the sake of argument, let us assume Ludwig van Beethoven, as well). Yet many of us eventually come to a position from which we feel we can speak about Beethoven. Can we say anything "developmentally" about how we get there? My own stab at answering this question (heavily informed by the work of Gerald Edelman) is that we have the ability to build up our own experience base; and, as we do so, we begin to form perceptual categories, which we can invoke to inform our speech. However, experience does not come overnight; so it would probably be unreasonable to expect a newspaper critic to bring himself up to speed on Messiaen for the sake of submitting a review on time!
Nevertheless, if we move beyond the specifics of Messiaen or Beethoven, my "Platonic" view of knowledge allows for the possibility that we can prepare ourselves for the task of describing new music (unless it springs from an abstraction that is deliberately removed from all experience bases). This takes us back to my favorite quote from Stravinsky:
Others let the ears be present and they don't make an effort to understand. To listen is an effort, and just to hear is no merit. A duck hears also.
In light of Edelman's insights, what separates us from ducks is the richness of perceptual categories we can manage in the course of our perceptions. From a strictly personal point of view, it took me quite some time (including several feeble efforts at trying to play some of the stuff) to build up some perceptual categories to inform my having anything to say (at least in Wittgenstein's sense) about Messiaen! Thus, what Stravinsky calls "an effort to understand" may ultimately come down to allowing oneself to acquire as broad an experience base of listening to (if not playing) music as "world enough and time" can allow, because it is only through those experiences that perceptual categories will emerge, primarily as a consequence of the cerebral cortex doing what nature has endowed it with the capacity to do; and, the richer the base of categories we acquire, the less we have to worry about passing over in silence!