Gebaseerd ook op een vraag van m'n dochter van 3 zoals bij Dorske: Waarom rijmt 'acht' op 'nacht'? Nee geen toeval, want 'huit - nuit' 'eight-night'.

Je vergeet er nog een paar:
Spanish: ocho noche
German: acht nacht
Italian: otto notte
Portuguese: oito noite

Ik vond de volgende reactie in de bron:
EIGHT - "eight O.E. eahta, æhta, from P.Gmc. *akhto(u) (cf. O.N. atta, Ger. acht, Goth. ahtau), from PIE *okto (cf. Gk. okto, L. octo, O.Ir. ocht-n, Bret. eiz, Skt. astau, Avestan ashta). Klein calls it "an old dual form, orig. meaning 'twice four.' "

NIGHT - "night O.E. niht (W.Saxon neaht, Anglian næht, neht), the vowel indicating that the modern word derives from oblique cases (gen. nihte, dat. niht), from P.Gmc. *nakht- (cf. O.H.G. naht, O.Fris., Du., Ger. nacht, O.N. natt, Goth. nahts), from PIE *nok(w)t- (cf. Gk. nuks "a night," L. nox, O.Ir. nochd, Skt. naktam "at night," Lith. naktis "night," O.C.S. nosti, Rus. noch', Welsh henoid "tonight")."

Which, on close examination, shows that the roots of both words are similar (to some extent), but I reckon that's pure coincidence. Sounds within a language often shift not just within a word, but within many words. For instance, the "c" in many Latin words became a "p" in Romanian. That's why there are Romanian words that become more familiar to speakers of English or Romance languages if you recognize this fact. "Apa" = "water," but when you think of words like "agua" or "aqua," with more of a hard "k" sound, you can see the link.

Similarly, "eight" is "opt" in Romanian. "Night" is "noapte." But obviously, these are just two words that had a "k" sound (or something similar) in Latin and Greek. I use Romanian, as it's not one of the examples given, but it fits the pattern. It LOOKS like all those languages with their different words share this similarity . . . but in reality, it's just a carry over of the similarity of "night" and "eight" in their Latin or Germanic roots, with phonetic changes peculiar to each language occurring to the pairs. (For instance, French tended to drop "k" sounds before "t.")

That "no eight" comment is just crap, in my opinion.

Here's two more examples that don't fit:

Hungarian (a non-Indo-European language):

eight = nyolc
night = este or éjszaka

Bosnian (an Indo-European language):

eight = osam
night = noc
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Met andere woorden, het lijkt erop dat het toeval is.