I’m sorry to ask such an evident thing, but I’m confused now about it.
So, how to pronounce ‘the’ in front of United States / US / UK.
According to the rule, if ‘the’ is in front of a word starting with ‘u’ which is pronounced as ‘ju’ then we have to pronounce it in the normal way. (the table = the university)
However, I can hear very often to pronounce it with an /i/, e.g. the /i/ US. But here ‘u’ is pronounced with ‘ju’? So why to change the normal pronunciation of ‘the’. Or isn;t it correct to pronunce it with /i/?
As you say ‘the’ is pronounced long before a vowel sound really because it is easier to say. The use of ‘the’ pronounced long before a sound that is not a vowel sound is often used in British English as a form of affectation. It is of course pronounced so when you are indicating that the following noun is unique as in: I’m not talking about just any old Mr Gates but THE Mr Gates.
“The” is pronounced [ðə] before a consonant sound and [ði] before a vowel sound. Words like “university” and “unit” begin with the consonant sound [j], as you point out, so you need to use [ðə] before them. The same is true of “US”, because that word also begins with [j]. Note what Alan said about the use of [ði] before words with consonants.
There are some places in the world where some native speakers put a glottal stop before every word that begins with a vowel, and so they say [ðə] before all words, since, with that glottal stop, all words begin with consonants for them. This is not standard speech, however.
Yes, added to what Jamie said, we can also use the [ði] pronunciation before a consonant for variation - in cases of emphasis, for example (“this isn’t just any old car, this is the car”).