To the grammer/spelling freaks out there

'Firstly' isn't a word.

f7

Err... yes it is. It's an adverb and you often use it to introduce points. Where did you get the idea it isn't a word? (Granted, the OP spelt it wrong - but spelt correctly as you have it definitely is a word)

Unfortunately, due to continued colloquial use and its logical construction, it has crept into formal use. It is, however, commonly known not to be a traditionally correct English word. The examples in my previous post further highlight this point.

The earliest example of its usage cited in the OED dates from around 1532. How long does a word need to have been around for in order to be "traditionally correct" in your book?

Would you say that 'electronical' ,'emo' or 'shemale' are words?

18th- and 19th-century lexicographers (well, people in general, really) took an incredibly fussy and prescriptive approach to spelling and etymology, and sometimes they did in fact get things wrong. So just because Mr Smart said that this is how the word came about that doesn't necessarily mean that's what really happened.

Why should the opinions of a prescriptive 19th-century lexicographer count for more than the fact that by then it had already been used for several centuries, though? He was certainly wrong about the "some late authors" bit - there are 305 results for pre-1700 usage of 'firstly" on the EEBO database.
18th- and 19th-century lexicographers (well, people in general, really) took an incredibly fussy and prescriptive approach to spelling and etymology, and sometimes they did in fact get things wrong. So just because Mr Smart said that this is how the word came about that doesn't necessarily mean that's what really happened.

Lots of words which seem perfectly "correct" today turn out to have slightly dodgy origins if you look back far enough, but that's how language works. It changes. Maybe 'firstly' was an erroneous 16th-century formation, or maybe it was originally a regional variant, but the point is that it is a perfectly good word to use now, so there's no reason to get hung up on its origins, really. Just because it may have been wrong in 1532 - and we don't even know for certain that it was - that doesn't mean it's wrong now, surely?

'firstly' wasn't included in Johnson's dictionary (1740s or something?), is that not a more forceful point?

Of course it's not; if we excluded words that Johnson didn't happen to notice we wouldn't have much of a language, would we? He defined fewer than 43,000 words while the current OED has over 300,000 main entries.

The point is though that 'firstly' existed when Johnson compiled the dictionary but he chose not to include it. I dont think he would have completely missed it!!

'Firstly' isn't a word.

f7

Unfortunately, due to continued colloquial use and its logical construction, it has crept into formal use. It is, however, commonly known not to be a traditionally correct English word. The examples in my previous post further highlight this point.

Not at all - Johnson was criticised at the time (he famously deliberately omitted such words as bang, budge, fuss, gambler, shabby and touchy ) and a whole episode of Blackadder was focused on him and his omissions. Or are you claiming that fuss is not a valid word because Johnson omitted it?

GTFO, I only do erotic lit.