One of the amazing things that happen in the other life is that when spirits talk to us humans, they do so in our native language. They speak it as easily and fluently as if they had been born in the same land and raised with the same language, whether they come from Europe or the Near East or some other part of the globe. So do those who lived thousands of years earlier, before the language even existed. In fact spirits have no idea that the speech they use with us is not their own native tongue. They use our secondary languages too, but beyond these, they are not capable of producing one syllable of another language, unless the Lord gives it directly to them. Even babies who die before they have really learned any language at all talk this way.
The reason, though, is that the language that spirits are familiar with is composed not of words but of thoughts. This language is common to all tongues. When spirits are present with a person on earth, their individual thoughts fall into words the person knows. The thoughts agree with and adapt to those words so perfectly that the spirits have no notion that the actual words are not their own. They fully believe they are speaking their own language, when it is really the person’s language they are speaking. I have discussed these matters with spirits a number of times. All souls receive this gift as soon as they enter the other world. They can understand the speech of everyone in the whole family of nations, just as though they had been born in those nations, because they sense whatever a person is thinking. Not to mention other talents in which they excel even more dramatically.
That is why it happens after physical death that souls can converse and interact with everyone, no matter what the individual’s region or language was.
from Secrets of Heaven, Volume 2, Section 1637