Can anyone tell me an English word which corresponds with the pronunciation of upsilon. I am having trouble discerning the difference between its pronunciation and Latin u. Any time I look in a dictionary, all I see is a French or German correspondent.
I believe it’s pronounced like “oo”, sooner. 
The crude english tongue creates not a sound so delicate as the upsilon.
Depends on which era of the Greek language you are referring to.
From what I’ve heard of reconstructed pronounciation, in Homeric Greek upsilon is pronounced as the oo in soon, but in Attic Greek it changed to a vowel not used in the English language (in French it’s the u in Tu and in German it u with an umlaut). If you know no French or German, try rapidly switching between the oo (soon) and ee (see) vowels and find the vowel in the middle. In Modern Greek it’s pronounced as ee in see, bee, and tree. That is why everybody was calling Lysistrata “Lisistrati” in the Modern Greek production I saw of that play.
Then I suppose French is a crude tongue since it does not contain any dental fricatives, and Greek as well since it lacks lingua-palatal fricatives.
There is no English equivalent.
To make the front /y/ sound do this: make your lips into the shape used for the sound /u/, as in moon. Then, without moving your lips, move your tongue into position to pronounce the /i/ sound in feet.
well, native English speakers know better, but I always pronounced coup more or less like ypsilon (but maybe I am just pronouncing it wrong hehe)