Great topic, Ziggy! I love languages and linguistics. I almost studied linguistics, and considered a career as an interpreter at one point. It's more of just a pet interest of mine at this point.
Steven Pinker has done a lot of writing on the so-called 'Universal Grammar', which he believes is decidedly instinctive. There are definitely some elements, such as parts of speech, that are common to all languages. I'll never read his book 'The Language Instinct', I don't think, because language, like love, is just one of those things I enjoy a lot better mystified than demystified.
One idea I've read that I find fascinating, is the theory that all words evolved from onomatopoeia (imitations of natural sounds with our voices). According to this theory, just as limestone is formed slowly from the accumulated and compacted shells of dead marine mollusks, language is formed slowly from accumulations of former onomatopoeia, whose meanings have shifted countless times. Although we think of them as trifling words, or barely even words at all, onomatopoeia are among any language's oldest words, and often survive, relatively unchanged in pronunciation and meaning, for many centuries. The ones found in Shakespeare and Chaucer are instantly recognizable to modern English speakers, and 'ah!' is listed in Cassell's Latin Dictionary as an expression of pain, even in Roman times.
A good example of this onomatopoetic fossilization are the many English verbs that begin with 'fl', that involve some kind of light brushing motion: fly, flip, flirt, flap, flow.
I love etymology. Having taken Latin, dabbled in Ancient Greek, and paid attention to the Indo-European roots listed in dictionaries, I often notice the etymological connections between words right away. I could never understand why people would write me off as a geeky know-it-all when I'd point out, for example, that 'jot and tittle' once literally meant the dot on the letter I and the bar on the letter T. I've shocked people by telling them the origin and meaning of their surnames, which sometimes even they didn't know (French and Italian names are particularly easy).
I'll give you a good example of the machinations my mind goes through, with regards to etymology. I was once on the phone at work with someone whose name I needed to write down. I misspelled it the way I heard it: Tedeski. It was correctly spelled Tedeschi. I had assumed it was Polish. It was actually Italian, and means 'Germans'. It might have been spelled the way I thought, if not for the fact that Italian doesn't use the letter k. It dawned on me that Mr. Tedeschi probably gets his name mispronounced a lot too -- we associate 'sch' with words and names of German origin, where it's the phonetic equivalent of English 'sh'. But in Italian it has no such orthographic significance; the 'h' is a silent letter that's simply there to keep the hard 'c' sound in front of the vowel 'i'.
Now here's the interesting part. I somehow knew instinctively that the similarity between the 'schi' on the end of Mr. Tedeschi's name, and the 'ski' on the end of many Polish names, was not a coincidence. And indeed I was right. A little research told me that pretty much any European words that end with the sound 'sk', or something like it, come from an ancient Indo-European ending for forming adjectives out of nouns. The English suffix '-ish', and the suffix '-ese' used for some nationalities, both come from this same root. It occurred to me that speakers of Western languages really have no idea how similar and closely related all of their languages are.
FWIW, Mr. Medeski, of the band Medeski Martin and Wood, is of Polish descent, and there are no people surnamed 'Medeschi' in US phone books. I inquired about this, just out of curiosity.
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