Not sure why Russian characters needs 6 bytes? I think it should also take 1-4 bytes only.
I remember this problem from 2018, and in some languages such as Roman, Greek, Hebrew, and Arabic, the number of words is less than the number of words in the English language, and the reason for this is that we have about 65,535 bytes limit per post (focus bytes, not words) in ASCII characters (completely compatible with the English language) each 128 characters are encoded using 1 Byte, but in some languages such as Arabic and Russian, where there are extra characters, which are expressed as 1920 characters, they are encoded using 2 Bytes, and thus the number of bytes consumed by characters in any local language becomes much higher than in the English language, and thus the number of characters in the English language more than other languages.
If your topic contains longer words, the words consume more letters and require more than one post.
Limits are in bytes like you can see in a guide of forum ad design. Byte is a common unit for limits in Bitcoin if I am right.
The maximum image size is 51200 bytes
https://bitcointalk.org/ad_design.phpAre you sure? For a long time I thought the limit was 2.5 MB