For example 9th 3rd 301st what do we call these special sounds? Is there a rule or reason for the differences? First noted in the late 18th.
Length, width, breadth, depth, wealth, girth, dearth all end with. When writing twentieth century using an ordinal numeral, should the th part be in superscript? Given that the two th sounds don't actually sound like a combination of t and h why was that particular combination selected or become adopted by the majority ?
When were numeric contractions for ordinals first used, as in 1st, 2nd, 3rd, 6th instead of first, second, third, sixth? Consider the th in thistle versus the th in this: Height, weight, thought, drought, sleight, sight all end with ‑ht. The former is unvoiced, while the latter is voiced.