Hebrew
a reader named Idan Zamir sent me this translation of the seximal system into Hebrew.
(X - voiceless velar fricative)
(š - voiceless postalveolar fricative)
(everything is in feminine because that's what we use in counting)
Numbers from one to twelve each have a unique name (with one exception), so here they are:
1 - axat - אחת
2 - štaim - שתיים
3 - šaloš - שלוש
4 - arba - ארבע
5 - xameš - חמש
10 - šeš - שש
11 - ševa - שבע
12 - šmone - שמונה
13 - teša - תשע
14 - eser - עשר
15 - kaf - כף - (there's no unique word for eleven. but the letter kaf has the value of elven)
20 - treisar - תריסר
Now, Hebrew has a different conjunction depending on the first letter of a word, so you will sometimes see "ve" and sometimes "u", don't be frightened.
21 - treisar ve'axat - תריסר ואחת
22 - treisar uštaim - תריסר ושתיים
23 - treisar vešaloš - תריסר ושלוש
24 - treisar ve'arba - תריסר וארבע
25 - treisar vexameš - תריסר וחמש
So! new words for larger multiples of six! I just changed the suffix "im" with the suffix "in", mainly because it's a familiar suffix in Hebrew for pluralisation.
30 - šlošin - שלושין
40 - arbain - ארבעין
50 - Xamišin - חמישין
So 43 would be for exmple "arbain vešaloš - ארבעין ושלוש"
What comes after xamišin vexameš? I decided to call 100 "Noga - נוגה", why? because by the Jewish tradition, the light God created in the first day shined for 100 (36 in decimal) hours, and Ziv is a Hebrew word for light, it's not very common in every speech so there won't be any confusion.
From here everything works like in the English system, so 5321 would be "xamišin vešalos noga treisar ve'axat - חמישין ושלוש נוגה תריסר ואחת". Hebrew uses the words million, milliard and so on so there won't be a problem using unexian (אונקסיאן), biexian (בייקסיאן) and so on, it's pretty straight forward writing them in the Hebrew alphabet.