>>10929969Language is just a means of communicating concepts that are common knowledge. We all know what a rock or a tree is but each language has a different word for it. However, if you walk up to a foreigner who doesn't know any English at all, hold up a rock with one hand while pointing directly at it with the other and say "rock" he will work out that when you say "rock" while holding one in your hand that the word you said means the same thing as the word for that item in your hand in his language.
Dolphins are not familiar with all the concepts that we have shared knowledge of. If it's too far removed from anything they are familiar with in their natural environment then they have no hope of understanding it. English is way too complex to for them to pick up. You have to teach them about the concepts the language is conveying before you teach them the language itself. In fact, many people from non-Eurosphere countries where English is not spoken as a first language say that English is the hardest to learn when it comes to syntax as the sentence structure and word order is so different from their own.
It's best to start the dolphins off off with pictograms like the ones our ancient ancestors used to record historical events and tell stories and that we still use today in the form of street signage. Then maybe over a few millennia of dolphin society evolving with the knowledge of pictograms and their meanings, they will be able to match the meaning behind those pictograms to the combinations of letters that make up the words we use to convey the same concepts those pictograms are conveying so they can pick the right ones to communicate with.