What language family was prior to proto-indo European?

There's no definitive answer to what language family came before Proto-Indo-European (PIE). We don't have direct evidence of any language that existed before PIE, making it impossible to definitively say what came before it.

However, there are several theories and ongoing research in the field of linguistic reconstruction:

1. The Nostratic Hypothesis: This theory proposes a "Nostratic" language family that predates PIE and encompasses several families, including Indo-European, Uralic, Altaic, and possibly others. This hypothesis is still debated and lacks conclusive evidence.

2. Other Theories: Other theories suggest possible connections between PIE and other ancient language families, such as Dene-Caucasian or even languages like Basque. However, these connections are also largely speculative and based on limited evidence.

3. The "Unknown Predecessor": It's also possible that PIE emerged from a language or language family that we have no knowledge of, perhaps leaving no traceable descendants.

The Challenges:

* Lack of Written Evidence: Languages prior to PIE were primarily oral, leaving few tangible records.

* Reconstruction Limitations: Linguistic reconstruction relies on comparing related languages and identifying shared features, but these methods become less reliable further back in time.

* Dating Uncertainty: Establishing the exact timeframe for PIE's origins is challenging, making it difficult to pinpoint potential predecessors.

In conclusion, we don't have a clear picture of what language family existed before Proto-Indo-European. The search for PIE's ancestor is a fascinating but complex field of study with ongoing research and debates.