I apologize if this question is a bit silly
There are a few instances in the bible were it says things like "And Jesus said: Talita kum, which means 'stand up little one' "
Today we know that every time Jesus is quoted directly like this his words were in Aramaic, which indicates that was probably his native language
But... did Medieval christians know this?
If an educated person were to read the Bible back then they would probably assume those words were in Hebrew, they had probably never even heard of Aramaic
Many christian scholars of that time showed interest in hebrew at some point but as far as I know no one ever showed the slightest interest in Aramaic, which is crazy since this was Jesus' native language... But it would make sense if they didn't know it was his native language
So, did they knew?, and if they knew, why didn't care about Aramaic?
I suppose the first thing you should have to ask is "who are we talking about, here"?
What would be interesting to try and find out, for example, if most Aramaic and Arabic-speaking Christians of the Middle-East were aware of the fact that Jesus spoke a form of Aramaic (Jewish Palestinian, to be exact), but I wouldn't exactly know where to start with that.
Anyway, from the context of your question I suppose you are talking about Christians in Europe. Although this is not directly my field of specialization, I have worked and taught a bit about the history of the teaching of "oriental languages" in Europe. But because I mostly focus on Arabic, I had to look up references to Aramaic myself.
Firstly, while there are parts of the Hebrew Bible (what Christians refer to as the Old Testament) that are written in a late Achaemenid Imperial Aramaic, it's actually a pretty small part. It is estimated that only up to six percent of the Bible is written in Aramaic. More specifically, it's basically parts of Ezra, Daniel and Jeremiah. On the other hand, the parts of Daniel that are in Aramaic are actually considered pretty important as they refer to prophecy. Being able to properly understand and interpret the Aramaic of these portions would be considered important. This would already lead me to intuitively say "a well-versed medieval Christian scholar would know about Aramaic".
But let's look beyond just intuition. In her contribution to the 2014 work A Jewish Targum in a Christian World, Judith Olszowy-Schlanger looks at the history of Aramaic studies in medieval Britain and France. She points out that sources for studying Aramaic were rare before 1150. What knowledge they had, they had mostly gained from studying with Jews, who were much more intimately familiar with Aramaic, as they would study that on a (near-)daily basis.
In 1311-1312, Roger Bacon successfully pleaded at the Church Council of Vienne for the founding of chairs in Greek, Hebrew, Aramaic and Arabic. There were two reasons for this: to train missionaries and to improve biblical exegesis. In fact, Roger Bacon himself showed a particular interest in the Aramaic portions of the Book of Jeremiah, going out of his way to provide a Latin transliteration and markdown, as well as a translation in different languages.
Lastly, as an important caveat, I have to point out that medieval scholars' understanding of linguistic relatedness was..sketchy, to say the least. The term "Aramaic" does not really appear until the 19th century. Before then, the term Chaldean was used, which can refer to Aramaic as a whole, or Syriac (a specific form of Late Aramaic) more specifically.
To sum up: yes, learned medieval Christians were likely aware of the non-Hebrew parts of the Hebrew Bible.
Sources:
Irwin, R. 2006. For Lust of Knowing: The Orientalists and their Enemies
Suchard, B. 2021. "The Origins of the Biblical Aramaic Reading Tradition"
Olszowy-Schlanger, J. 2014. "The Study of the Aramaic Targum by Christians in Medieval France and England"