Why do Americans seem to use the word “delicious” less often than I do?

I am a foreigner and now I am in America. I always use the word delicious whenever I like food. For example:

This meat is so delicious!

But one of my friends, who is not a native speaker, once told me that Americans rarely use delicious. The more frequent expressions would be “This meat is good” or “This meat is yummy.”

Is delicious more of a British English word than an American one?

In my experience as an American:

We do use the word delicious fairly often. It is not at all unusual or strange.

Its use compared to the more general words "good" and "great" is dependent on context.

For example, if my friend asked me "how's the food?" and I enjoyed the food, I'd more likely use "it's good!" or "it's great!" and reserve "it's delicious!" only for when it's exceptionally good. And this is mostly the case, that "delicious" is simply "more good" or "very good." A similar word would be "scrumptious." It's used by many, but it's just less usual because it implies that the food is unusually good.

However, if nobody prompted me, and I simply want to proclaim that the food I'm eating is good, I'd be more tempted to use the word "delicious" because it's specific to food, so it's more easily understood what I'm talking about.

As for "yummy," "tasty," and other such specific words... it's hard to say if they're common. I rarely hear "yummy" but I hear and say "tasty" quite often. Definitely more so than "delicious."

I do not often use delicious myself, but neither do I consider it unusual or "foreign" in any way.

It may not be that popular in your friend's circles, but the Corpus of Contemporary American English has twice as many results for delicious as it does for tasty and yummy combined. The relative numbers are not very different from those in the British National Corpus (though yummy is much less common in the latter). It does have an extra syllable, which has probably contributed to the use of delish.

There are many ways to approve of the taste of a food or meal; delicious is, if anything, so generic and unspecific that it is interchangeable with saying something tastes good. So in advertising, food journalism, and the like it is true that delicious may be unfavored compared to more colorful words like delectable or ambrosial or scrumptious or toothsome.

As if we Americans needed any more encouragement to eat.

If I may submit a couple of Ngrams for comparison.

Corpus: British English

Corpus: American English

I was not surprised to see that the usage of the word 'delicious' more or less follows the same trend between both lexicons corpora. I was a little surprised to see that the term is slightly more popular in American usage than across the pond.

I cannot speak for the usage of any term in Great Britain, but I can say that in my circles, 'delicious' sees frequent usage. Yummy for me is more for when I am trying to convince my 1-yo son to eat his peas.