There are seven blessings pronounced upon Mary, in all.
Three are from Gabriel who says 'favoured', or it may be translated 'highly favoured', the word recorded by Luke, in Greek, being charitoo, Luke 1:28. Then the word eulogeo, 'blessed' is recorded, of Gabriel's words, in 1:28. And finally, the word charis is recorded 'favour with God' in 1:30.
Simeon also blesses Mary and the child, eulogeo being the Greek record.Luke 1:34.
Elisabeth is recorded saying 'blessed art thou among women' with the word eulogeo; then 'blessed is she that believed' using makarios. Luke 1:42 and 45.
Lastly, and seventhly, Mary states that all generations shall count her 'blessed', makarizo being the Greek record. Luke 1:48.
Mary was closely related to Elisabeth, the word suggenia suggesting, possibly, cousin, but not necessarily. Elisabeth was of the daughters of Aaron; thus Mary must have had at least one parent who was of the tribe of Levi. Elisabeth lived in the hill country of Judaea, almost certainly Kirjath Arba, which is Hebron, the city given to the Levites out of Judah's inheritance.
Thus, presumably, Mary grew up in Hebron, among those who were descended of Aaron and Levi, and would, certainly, have spoken Hebrew. Later she is found in Nazareth as an adult where she may well have, also, spoken the dialect Aramaic which is Hebrew mixed with Chaldee, the result of the Babylonian captivity. Galilee was also called, 'Galilee of the Gentiles' being close to, and influenced by, Greek speakers.
Hebrew, Chaldee and Aramaic are dialects, not distinct languages. Anyone who knows one will speak, or pick up, the others.
It would not be unreasonable to suppose that the Archangel, come to make a most singular announcement to a woman of the tribe of Levi, and perhaps, like Elisabeth, being also a daughter of Aaron, would have spoken - assuming this was a matter of audibly conducted speech - in Hebrew.
In which case I expect the word which Mary heard would have been chen, or a derivative of chen, the Hebrew equivalent of charis.
But there still remains the matter of the word charitoo, the precise one recorded by Luke to document the wording. It is only used once more in scripture, in Ephesians 1:6, 'accepted in the beloved'. Some concordances list the word twice in Ephesians due to the KJV translation 'made accepted' which is two words, requiring two listings.
Thayer's Lexicon says of charitoo : to pursue with grace, compass with favor; to honor with blessings
Liddell & Scott (1864 American Edition) gives 'highly favoured' and mentions that it is used in the Septuagint but I have not been able to determine where. It may be an apocryphal book.
This subject is dealt with in detail here :
Translation of Luke 1:28 "Greetings, favored one!"
The first answer is the one that was accepted and it is quite comprehensive.