These are not incantations, but words ‘eight’ and ‘nine’ in Estonian, a language I am learning.
While learning numbers, I had a huge difficulty remembering the words for ‘eight’ and ‘nine’: which was which?
Then it dawned on me that inside kaheksa hides kaks, ‘two’, in its form kahe, and inside üheksa hides üks, ‘one’, in its form ühe. Clearly, kaheksa (8), was constructed as ‘2 (kahe) out of 10′, and üheksa (9) as ‘1 (ühe) out of 10′.
But ‘ten’ in Estonian is kümme, where does this mysterious -ksa come from?
It took me some time and effort to find reliable sources of information, given that my Estonian is basic and I have only faded memories of Hungarian, another Finno-Ugric language on my list.
Estonian etymological dictionary gives etymology for kaheksa and üheksa, and proposes two explanations: -ksa derives from *detsa, a proto-Iranian (hence Indoeuropean) word for ten (compare word for ‘ten’ in other Indo-European languages). Alternatively, –ksa is interpreted as an old negation form.
Curiously, it is believed that seitse ‘seven’ might be a loanword from Baltic or Slavic languages, which are of the Indo-European family (compare Russian семь, Czech sedm, and Latvian septiņi), whereas numbers one to six are of of Finno-Ugric or Uralic origin.
This heterogeneity of construction and origins of the first ten numbers is sometimes interpreted to suggest a base-6 system among ancestors of Finno-Ugric people — apparently, a heated linguistic debate.