What does the use of っ imply?

[cmertb]

Sorry if this has been asked before, I haven't been able to find it. After starting to read manga in the original, I couldn't help but notice that writers do love to use っ at the end of almost every sentence. E.g. はっ。。。はいいっ。すいませんっ My guess is it indicates some kind of special intonation, but I have no idea what kind exactly. Could anyone enlighten me?

[boxofmochi]

It's more of the sound:

「は。。。」is just like the questioning asian "Haahhh...."
「はっ」is more like a question with a show of surprise "Ha-"
The small っ is like you're cutting yourself off. In english, we might use "o-okay" to show a stutter; in Japanese you might see that like 「はっ。。。はい。。。」(Y-yes...)

[cmertb]

This works with はっ。。。はいっ

But what could possibly be cut off in すいませんっ?

[boxofmochi]

Same thing - like saying it with a bit more emphasis, or with a sharper edge at the end.
「すみません」"Excuse me"
「すみませんっ」"Excuse me--"
It's not something that's really used in English, but in Japanese it communicates enthusiasm, or a bit more force or haste.
For example, someone might say 「すみませんっ」to hastily excuse themselves, but use 「すみません」if they're not really in a hurry and can spare the time to be more patient.

If it makes things easier, you could think of the small っ as a tiny exclamation ! mark.

[cmertb]

OK, thanks for the explanation.