Yesterday I wrote about the song ‘The 12 days of Christmas’ and since then I’ve been thinking about the relationship between the cardinal numbers (one, two, three …) and the ordinal numbers (first, second, third …)
eleven > eleventh, ten > tenth, seven > seventh, six > sixth and four > fourth simply apply the basic rule of adding ‘th’. nine > ninth has an extra spelling rule of dropping the ‘e’, broadly consistent with many other spelling rules which drop a silent ‘e’ at the end of a word when other letters are added. twelve > twelfth drops the ‘e’ and changes the ‘v’ to ‘f’. Here we move from simply considering the spelling, to considering the spelling and the pronunciation together. In all of these words, ‘th’ represents /θ/, which is an unvoiced consonant, whereas the ‘v’ of ‘five’ is voiced. Very often when an voiced and unvoiced consonant fall together in a word, one will change its voicing to match the other. Here, the ‘v’ /v/ of ‘twelve’ changes to ‘f’ /f/. five > fifth drops the ‘e’, changes the ‘v’ /v/ to ‘f’ /f/ and shortens the /aɪ/ to /ɪ/. eight > eighth is intriguing. It really should be ‘eight’ + ‘th’ = ‘eightth’ – and that’s actually the way we pronounce it, at least in careful speech. three > third are recognisable as being related, but something strange has happened; whether a change in pronunciation led to a change in spelling (probably), or vice versa. (There’s lots more information about Middle English and Old English and other Indo-European languages which I won’t go into.)
Clearly, with two > second and one > first, something very strange happened; these words are clearly unrelated. ‘Second’ derives from Latin ‘secundus’, which in turn is related to ‘seq’ of ‘sequence’. ‘First’ derives from ‘fore’ + ‘est’, which makes the phrase ‘first and foremost’ almost tautologous.
But there’s something else about the pronunciation of these words. /θ/ is an interdental consonant, made with the tip of the tongue between the teeth. The previous phonemes are all made with the tongue elsewhere, which either means a compromise of some sort, or a quick flick of the tongue between where it already is and where it has to be for the /θ/. The most complex is ‘sixth’, which actually has three tongue positions – one for the /k/, one for the /s/ and one for the /θ/. Add /d/ on the beginning of ‘day’ and the tongue has to do four different things in quick succession. In fact, I suspect that most people, unless they are speaking very carefully, actually say ‘the sixday /sɪksdeɪ/ of Christmas’.
So, should we have ‘oneth’ (or ‘onth’), ‘twoth’ and ‘threeth’? Wiktionary includes ‘oneth’, as ‘archaic, nonstandard’, ‘twoth’ as ‘nonstandard’ and ‘threeth’ as ‘rare, nonstandard’. It also includes ‘zeroth’ and ‘zeroeth’.