Why is the proposed relationship between Indo-European and Uralic languages uncertain?

The proposed relationship between Indo-European and Uralic languages remains uncertain and speculative among linguists for several key reasons:

• Sparse Lexical Evidence: While there are some resemblances in basic grammatical elements—such as personal pronouns, verb endings, and the accusative case ending -m—the lexical evidence (shared vocabulary) is extremely sparse.1
• Extreme Time Depth: If a genetic relationship exists, the two families must have diverged thousands of years before the breakup of Proto-Indo-European, making it difficult to find reliable evidence.1
• Typological vs. Genetic Similarity: Although the two families share certain typological features, such as the use of many suffixes and a lack of prefixes, typological similarity alone is not considered proof of a genetic relationship. Similarities in structure can often arise through language contact rather than common ancestry.123

Because of these factors, most scholars do not consider a connection between the two families to be soundly established, and there is currently no significant evidence to support broader groupings like the Nostratic hypothesis that would encompass them.14