For a person to be declared “a Saint” there is very stringent, direct and specific occurrences which must be discovered, which is why it generally takes many years for anyone to be declared a saint. One of those must be a miracle that is directly attributed to the person, before they are declared a saint. For instance, in prayer a family or individual may request a person who they believed to be Holy on earth, but who has died, to intercede on their behalf and petition from JESUS the favor of a healing. Now this healing must be of a nature such that the original disease is of record with the medical authorities, and the disease must of the nature of being incurable by medicine, e.g. medicine has failed or was not available for the disease. However, after praying there is an immediate cure, which the “doctors” declare as unexplainable in any medical terms - they can’t figure out why the patient was cured so quickly of such a dire disease.
In the above sense, yes the saints have indeed spoken to us through their actions on our behalf.
The apparitions of Mary have occurred, on average, once every 50 years since She left the earth, the first apparition was to St. James the Apostle when he was so discouraged with his then mission, and Her message to St. James and to us over the eons, has not changed, “believe in JESUS, love JESUS, trust in JESUS, do JESUS work, pray for JESUS intercession, honor JESUS…etc”. Her message is always to call us back to JESUS.
Just as in approving saints, there are very serious considerations which must be met in order for the Church to declare an apparition as valid, yes the Virgin Mary did come to earth and appear at this or that location. One of the most written about and verified was in Portugal at Fatima. Mary announced a miracle to be on a certain date, and many skeptics, journalists and non-believers were present when the miracle occurred, and it was well written about and document and those articles are available or discovery as they have been archived.
A second very well documented apparition was in Mexico where the serape of Juan Diego is still available for review. In this apparition She was called the Lady of Guadalupe and She appeared pregnant and convinced the Indians to stop sacrificing their babies. A scientific review of the image She left on Juan Diego’s cape - which although being made of reeds, has never deteriorated - revealed through a microscopic analysis the picture of a kneeling Juan Diego as reflected in the pupil of each of Her eyes in this image.
Also for your research I would suggest you review the apparition that is being reported in Medjugore, which according to all reports has been continuing for almost 10 years and is being reported as the last of Her visits before Her SON, JESUS returns - which is why the apparition is supposedly lasting so long. This apparition is NOT supported by the local Catholic Bishop as being true, but that same position was likewise assumed by the Bishop at Fatima originally as well. In this apparition the Virgin Mary, if She is appearing, has advised that She will leave an indestructible sign when the apparition ends, as proof. So, we need to each decide on our own how to approach this apparition and then wait for the sign, if it comes. One test is the messages She leaves, which still point to coming back, returning to, believing in and loving Her SON, JESUS - the same message She has always been teaching and pleading with us to observe and live.
Hope this helps.