Each new language uses a different namespace for hashing its script This is because you could have a language where the same bytes have different semantics So this avoids scripts in different languages mapping to the same hash Note that the enum value here is different than the enum value for deciding the cost model of a script https://github.com/input-output-hk/cardano-ledger/blob/9c3b4737b13b30f71529e76c5330f403165e28a6/eras/alonzo/impl/src/Cardano/Ledger/Alonzo.hs#L127