What is the correct way to say 小さい『つ』?

Question

This is a two part question.

1.) When spelling out a word in kana, what is the correct way to call the small つ (for example the small っ in ちっちゃい)?

I only have experience with my Japanese friends using the informal sounding

小さい『つ』

or

ちっちゃい『つ』

Is there a formal grammatical term for this "character"?

2.) If there is, but in reality it sounds too academic, which term would be the most immediately understandable in an informal setting?

Answer 1

It appears that one more-formal way to describe characters like 「っ」 is to use the phrase 「小書{こが}き」文字{もじ} or simply「小書{こが}き」。 So, in the case of 「っ」, it would be something like: 小書{こが}きの「つ」.

But in an informal context, something like「小さい『つ』」would probably get the point across.

For more information, there is a more detailed writeup by a user named "nullstrings27" that further explains 小書{こが}き文字{もじ} in general.