Where does the t in the front of the word “eighty” come from?

Answer

Dear Barthold,

the t in the front eighty is indeed a bit strange. The probable explanation is that the t, like the suffix tig, is a remnant of an old form meaning ‘ten’ or ‘ten’. Such prefixes and suffixes tend to gradually erode, and when they have become completely or almost completely unrecognizable, language users look for a replacement. In this case we can imagine the following scenario: initially (the predecessor of) Dutch for the meaning ’80’ had a word that consisted of an element meaning ‘ten’ followed by an element eight. The first element, however, became reduced and was therefore reinforced by another element that also meant ‘ten’, this time at the end of the word.

The dialect situation you describe fits well into this picture. In Standard Dutch the t-prefix has completely disappeared except in eighty, but in your dialect you can still see remnants in forty, fifty, tzestig, seventy and ninety. This shows, first, that the t is indeed characteristic of the tens: no one says five, thundred, or seven thousand; and secondly, in the comparison between the dialect and Standard Dutch, we also see how the reduction took place. An element can be reduced most quickly in a context where it is least noticeable: for a vowel the t is more noticeable than for a consonant – so even the (in this case) more progressive Standard Dutch retains the t in eighty; but for a sound similar to t as the d in thirty, no t can be heard even in the (in this case) more conservative dialect. A similar reasoning explains why you say ninety in dialect, but probably not ninety-four: a consonant is more noticeable at the beginning of a word than halfway through, and is therefore reduced less quickly at the word start than in the middle.