A correspondent writes from the USA to say he's noticed British English words and phrases increasingly entering public and written discourse. He gives as examples He was sacked instead of He was fired, gone missing, and such slang words as snarky. In particular, he says he's beginning to hear amongst rather than among, and wonders whether there's a difference between British and American English in this respect.
There certainly is. A table in the Quirk Grammar (9.21) shows amongst occurring ten times more frequently in British English, and this is confirmed by later corpus studies. In the huge COCA corpus (Corpus of Contemporary American English) we find 2405 instances of amongst compared with 144,461 instances of among - 1.7 per cent. This compares with 4449 instances in the British National Corpus compared with 22,385 of among - 20 per cent. On the other hand, those 2405 US instances spread pretty evenly over the past decade, so there's no evidence of any kind of very recent dramatic increase. I'd be interested to hear what US readers of this post think.
In the UK, my impression is that all the -st words are reducing in frequency. They began as a development of an ending attached to the base form: among + an -es genitive. We see that ending still in besides. Then in the 16th century, people evidently felt this was related to the -est superlative form, as gradually we find the -st ending used. We see it also in against, where it's the standard form, and in amidst (vs amid) and whilst (vs while), where usage varies. Fowler thought that these differences might be explained with reference to pronunciation - the -st forms would be used when the following word began with a vowel - but this isn't supported by the large corpus collections. The variation in standard English seems to be primarily stylistically conditioned: some people like the sound of whilst; others hate it. There's also a chronological factor: the -st forms tend to be found in older texts and among older people. And there's a great deal of regional dialect variation too.
The OED makes an interesting point about amongst, suggesting a semantic nuance not found in among: 'generally implying dispersion, intermixture, or shifting position'. So, I walked amongst the crowd would suggest a rather more active moving about than I walked among the crowd. If this is so, then I'd expect to see an increase in the proportion of amongst usages in contexts where these notions are dominant; and a quick dip into Google suggests that this is the case. With among(st) a group the proportion of amongst usage rises to 12.6 per cent; with among(st) the waves it is 45 per cent. With talk among(st) yourselves, the usage actually reverses, with amongst being four times as frequent. If there is a trend in US English to use amongst, semantics may well be an influential factor.