Which European language is more strange and isolated?

[Crimean]

Basque and, of course, all languages of the North Caucasian family.
An interesting coincidence is that many researchers are trying (tried?) to combine them into one proto-family.
If you do not speak, for example, Kabardian or Avar from childhood, as an adult it is completely impossible to learn at an adequate level.
From the listed my vote goes for Finnish.

[Blondie]

By the way 39,5% of hungarian vocabulary is Indo-European (german, slavic, romance etc), 9,5% altaic and only 21% uralic:
https://en.wikipedia.org/wiki/Hungarian_language

The finnish or other uralic languages are not such indo-europaized like hungarian. An average hungarian person (who never learned foreign languages) can understand many german or slovak word without any translator. As fluent hungarian speaker i can understand 15-20% of slovak language, but only slovak other slavic languages sounds very strange.

[Blondie]

I prefere genetic preservation, in my case.

Yes genetic + identity. European genetic doesn't matter if you have no european identity

[Crimean]

By the way 39,5% of hungarian vocabulary is Indo-European (german, slavic, romance etc), 9,5% altaic and only 21% uralic:

But Hungarian phonetics and grammar makes these borrowings indistinguishable from primordial words for non-Hungarians (at first sight).

The finnish or other uralic languages are not such indo-europaized like hungarian. An average hungarian person (who never learned foreign languages) can understand many german or slovak word without any translator. As fluent hungarian speaker i can understand 15-20% of slovak language, but only slovak other slavic languages sounds very strange.

Is Russian at least a little understandable for you (if only because of the abundance of Latin and Greek vocabulary)?

[Blondie]

Is Russian at least a little understandable for you (if only because of the abundance of Latin and Greek vocabulary)?

No, only the written slovak language is a little bit understandable, not other slavic languages. Slovaks and hungarians lived in same country between 9-20 century of course they have tons of same word.

[Mingle]

But it is a language that has nothing to do with other (I think, maybe I am wrong but it is extremely particular IMO). Which other Euro language is similar?

Polish is a Slavic language, you didn't know that? Its most similar to Czech and Slovak.

Polish isn't that strange to me. The only reason it may look weird is because of its orthography. It uses a lot of weird looking letters whereas other Slavic languages with the same sounds don't use those letters.

[Cristiano viejo]

Polish is a Slavic language, you didn't know that? Its most similar to Czech and Slovak.

Polish isn't that strange to me. The only reason it may look weird is because of its orthography. It uses a lot of weird looking letters whereas other Slavic languages with the same sounds don't use those letters.

that is what I mean. Exactly that. They almost dont use vocals. It is strange as fuck.

[Mingle]

Not for me. Basque language uses a lot of Castilian words, just Basquecized, and are very easy to translate for Castilian speakers. This does not happen with these other languages to us.

All the languages in the poll use a lot of foreign words. Finnish has a lot of Swedish influence whereas Hungarian has a lot of German and Slavic influence. Greek influenced the vocabulary of basically every European language along with Latin, so I don't know why its even in the poll.

[Mingle]

that is what I mean. Exactly that. They almost dont use vocals. It is strange as fuck.

Its just their writing system. These sounds exist in other Slavic languages. They should probably reform their writing system.

[Mingle]

By the way 39,5% of hungarian vocabulary is Indo-European (german, slavic, romance etc), 9,5% altaic and only 21% uralic:
https://en.wikipedia.org/wiki/Hungarian_language

What about the remaining 30%?