There must be some links between French and English where in French, the formal version is "vous" which sounds like "you" and the informal is "toi" which maybe sounded like "thou" in the past. (The 'th' has no equivalent in French)
Pronouns tend to be some of the most fixed words in a language, up there with numbers and basic words like for "water" or "mother". They undergo sound change, and shifts like how English lost thou, but they are almost never replaced wholesale.
All those languages are in fact descended from a common language spoken several thousand years ago. About half of the world today speaks a language in the Indo-European language family.