That "j" is the sound we normally use "y" for in English (in their international phonetic alphabet, "j" follows from its origin in the Roman alphabet where it was just a different way to write "i" and Julius was pronounced "yoo li oos", if I remember right, it's hard to remember clearly that far back.) Anyway, that "j" is not for everyone. If you pronounce "Tuesday" the same as "two's day", then they're not talking to you - that's why the parentheses, for the dialectal variant that has dropped that sound and pronounces "u" the same as "oo" after alveolar consonants like d, t and n.dictionary wrote: ˈt(j)ubə
If on the other hand you do come from a dialectal region where "tube" would have that "y" sound, do you also pronounce "tuba" like that?
The dictionary can be wrong. I'm not talking about adopting common mispronunciations and misunderstandings of words, which they also do. They also take shortcuts and copy each other's errors instead of checking up on the facts (consider for example the common definition of espresso.) I'm not sure what I think about this one. I suppose the "u" vs. "oo" story goes back several hundred years to before modern English, and the tuba came along much later. Modern English spelling is more historic than orthographic, and the spelling of "tuba" can't be taken as an authoritative guide to its pronunciation.




