As I have said elsewhere, I think that for the most part any memories we have that predate acquisition of language are not going to be recognizable to us when we do remember them.
Most of our accessible useful memories are encoded with a combo of visual, auditory, and other sensory data, emotional data, and cognitive stream (the interp we gave to it all at the time it was happening), the latter formed of concepts we learn along with language.
I am not going to make those annoying sweeping statements like “No one can remember events before they were 3 years old”; but I think it is rare for a person to know what they’re remembering when they have such memories, to make any kind of sense of them.
Consider: go to the library and pick up a book written in a language that uses an alphabet you have no familiarity with. Casually examine a few pages. (Not deliberately exerting yourself to memorizing the shapes of the ink on the page, though). Now go take a night course and learn the language well enough that you can read its text with moderate fluency. Can you now recall the phrases and ideas from the pages you saw before you started the course?
So it is, I think, with memories formed before we have language. They get formed, but without a “narrator” stream-of-consciousness track embedded. Emotional content, yes, but not that self-referencial “OK this is what’s happening” soundtrack of our life thingie that we usually mean when we speak of “conscious thought”.
For thosoe who are pretty sure they recall material from preverbal stages of their lives, note that I bracketed off an exception in my allegorical example. If for some reason when you were in the library you did stare at the foreign-language text with such intensity, or so often, that you could remember the then-meaningless shapes from the paper at the later time when you could know what it meant, you could indeed realize what the text had been saying. The allegory is simpler than what we’re actually talking about, but it still seems a reasonable parallel.
But I would think it would be rare, and I think it’s no accident that most us remember back to no earlier than around the age when we became truly verbal people and could think about thoughts we had had yesterday, etc.
One other contributing factor to the rarity of successful post-verbal processing of pre-verbal memories is (IMHO) that we don’t tend to re-analyze memories in general with the additional knowledge we’ve acquired since they were formed.
Example: when I was about 8 my Dad said the car’s engine had a problem, “the rods are knocking”. I had seen the car with the hood open and the air cleaner was the most prominent thing and therefore represented “car engine” to me, so the image I had of “rods knocking” was of a bundle of metal sticks under the air cleaner, improperly loose so that they were rattling against each other instead of being bound firmly together. Decades later for some reason I was thinking of that car and whether it had needed a lot of repairs in comparison with a modern car and flashed back to the time when “the rods were knocking”, and the unedited/non-updated image was again of the bundle of sticks beneath the air cleaner despite, by then, having held connecting rods, bearings, pistons and piston rings, mains, rocker arms, and the rest of the engine assembly in my hands. Nor did I recognize that fact quickly. It took a conversation that dove into how engines of that era were made, in conjunction with “the rods were knocking”, before my mind, trying to compare that bundle of rattling sticks with a modern DOHC fuel-injected computer-timed engine, finally balked and went “huh?” and I realized the inaccuracy of the image. Connecting rods down in the engine block, not bundle of sticks under the air filter.
Extending that, I think probably even for infantile sensory data that we could recall with sufficient detail to interpret via the more complex info in our heads now, we simply don’t. Those memories don’t have thumbprints on them that say “I was 16 months old” so it’s not like we’re conscious that what we’re momentarily recalling is the view from our crib from when we were 16 months old. Instead, just a fragmentary snapshot (or brief video, perhaps) with no attached interp, kind of like an abstract oil painting, some shapes colors sounds and/or textures that float up in our mind with no particular reason to try to make sense of what it might have been.