Pronounciation of "unfortunately"

[Anne59]

Hi everyone, I've learned that the letter T in "unfortunately" has a CH sound. Can anyone tell me how I know which words with letter T should be pronounced CH or why does the T have a CH sounds? Is there a rule or a list? I can't find anything but could it be because the T is followed by U. Like in unfortunately, feature, future and picture?
I've managed to find out that it's because in these words the T is followed by U but there are exceptions like autumn, cactus, disturb, foetus, lettuce, momentum, and others. How can I know which pronunciation is right when I see a new word?

Thanks!

[Route21]

As an NES but not an English phonetics specialist:

I'd not specifically noticed it before, but "t" followed by the long vowel "u" could sound as though it's pronounced "chew...". It also occurs in words such as "tuna (fish)", "Tunisia", "tunes" etc.
If "t" is followed by a short "u" it's pronounced as in "tummy".

I would, however, defer to the phonetics specialists on the forum for a definitive answer.

Best regards
R21

[5jj]

/tj/ is often produced as /ʧ/.

[Raymott]

Hi everyone, I've learned that the letter T in "unfortunately" has a CH sound. Can anyone tell me how I know which words with letter T should be pronounced CH or why does the T have a CH sounds? Is there a rule or a list? I can't find anything but could it be because the T is followed by U. Like in unfortunately, feature, future and picture?
I've managed to find out that it's because in these words the T is followed by U but there are exceptions like autumn, cactus, disturb, foetus, lettuce, momentum, and others. How can I know which pronunciation is right when I see a new word?

Thanks!

To tell the truth, you can say all these "tuna, Tunisia, fortune" words with 't' and, as a Spanish speaker (in your case), you will be understood as well (or better) as if you try to pronounce them with "ch". With experience, you'll start saying it like a native. In fact, it's not even true that everyone pronounces these words that way, or that that is the 'correct' pronunciation. I say 'tyuna, tyuba' some of the time. It's probably not a real /ʧ/ that most people say anyway, but a more anterior sound.