Just a few additional notes on the already commented on this thread:

There is a BIP 39 Spanish word list, but the words are not equivalent to those found on the English version, nor are they interchangeable.
I’ve read about a few wallets that support creating your seed in a language of your choice (out of a few delimited options), but then these wallets I believe are very few, which is going to delimit options. I would therefore stick to the English list, due to having a much broader array of compatible wallets, facilitating migration if need be.

Some words translate different depending on the context. Since there is no context here per word, some words may present multiple alternative both on the way down (English to Spanish) and on the way back (Spanish to English). Spanish, as we know, may also have some minor variants between countries.

For example, "car" may be translated into "coche", but also to "carro", "auto" or "automobil". One of the given possibilities, "carro" could be translated as "cart", so depending on who is performing the translations may end-up with "cart" instead of "car" after completing the whole procedure.
 
Likewise, "token" could be translated as "ficha", but also as "símbolo", which, once translated back into English, could render a different word to the original.


It all depends of who does the translation process, but if the encryptor is different to the decryptor, the chances of one of these above examples taking place increases. Of course, using the BIP 39 list as a contrast reference may discard some of the reverse translation options when there are multiple available.

One other thing that may happen with some resulting string combinations is that, since there are no spaces between the words, the extraction process may present itself with a couple of options of breaking-up the words.
For example, after discarding the letters from the verse, we’d still need to reverse this:

"noimacasacdadrevsaremlapadartnesaglupazneugrevasemodinosorrohcacahcifadibeb"

Which is:

"bebidafichacachorrosonidomesaverguenzapulgasentradapalmerasverdadcasacamion"

Although there is little to no doubt on how to break-up the above into words, there may be other cases where one is presented various alternatives. Again, checking against the BIP 39 English word list should reduce the scope of dubious situations.