In my book I found both
むかしから within the span of a couple pages, in very similar contexts. What is the significance of that small-tsu (with regards to the meaning, not the pronunciation)?
The only place where I can find a distinction is in Google translate:
昔っから ==> Since old times
昔から ==> Always
Is the difference between these as subtle as it seems? Can one be used where the other cannot/sounds unnatural?
Everyone in the comments seems to agree that it's just a matter of emphasis, but I'll add the context @Tim requested. (I wrote it out like it appears in the book, but I added the bold)
The lines are said a few pages apart (which is actually some time), but both are said by two long time friends, one a fighter, the other a healer.
The first one is said by the fighter to the healer. She's saying that he wouldn't have known if anyone was following them.
The second one is said by the healer to the young boy that they're protecting. The fighter's been asleep and the other two are cooking.