Learn English – How to pronounce “what did you” in “So what did you dream about?” and other similar questions

/ˈəʊbɔɪ/ (oh + boy)

I have no direct information, but let's reason this out. The most modern pronunciation, as recorded in current British dictionaries, is /ˈəʊbɔɪ/ (hoe + boy), with the first syllabe being the same as that of oboe (/ˈəʊbəʊ/), apart from the initial h. This matches the pronunciation of other words or expressions from French beginning with haut: haut monde, haute couture, hauteur, … It actually matches the French (and Middle French) pronunciation of haut.

The second syllable, which sounds like boy, is also quite close to how Middle French boy sounded like (and very unlike the Modern French bois, /bwɑ/, like in bwana).

Now, would it be pronunced the same in Shakespearean times? Given that it came from Middle French, and in its most modern form still sounds like Middle French, I don't think it evolved in-between (and then went back to the French-like pronunciation). Also, the hits I could find for words of Middle French origin in Pronouncing Shakespeare's words: a guide from A to Zounds (like this hit) all seem to indicate pronunciations rather close to the Middle French.

Furthermore, etymonline says of hautboy that it is “frequently nativized as hoboy”. It seems to me that this support the pronunciation I put forth above.

If someone was expecting to hear a word pronounced in the same way as light - in other words as /laɪt/, and they then heard this word, they may very well mishear it.

The word is actually /laɪð/. The sound you hear at the end there is a voiced fricative, just like the sound /v/, but it is a dental fricative. We make it with our tongues touching the back of our teeth. It is the same sound we hear at the beginning of the word then. This sound is most frequently heard at the beginning of 'function words', the types of word you would study in grammar lessons:

• this, that, these, those, them, their ...

Sometimes, however, we hear it in lexical words (the kinds of words we often look up in a dictionary). At the ends of lexical words a particularly common spelling for this sound is -the.

As at least one commenter has said, there is often an alternation between a noun of the same root ending in -th, pronounced with the unvoiced dental fricative, /θ/ ( - the sound at the beginning of the word think), and a verb ending in -the, pronounced with its voiced counterpart /ð/. Compare the nouns:

• wreath /ri:θ/, sheath /ʃi:θ/

and the verbs:

• wreathe /ri:ð/, sheathe /ʃi:ð/

However, as will be seen from the Original Poster's question, this ending occurs with other parts of speech too. The target word lithe, with which we are currently concerned, is an adjective. We can also find nouns such as swathe/sweɪð/.