Question:
Answer:
The vast majority of those who follow the traditional rite of the Mass are in communion with the Holy See. Most of these are simply traditional Mass communities at various diocesan parishes.
There are also many communities of religious or clergy in apostolic institutes who follow the traditional liturgy, such as the Fraternity of St. Peter, or the Benedictines of Clear Creek in Oklahoma, or the Institute of Christ the King, and so on. In fact, only a tiny number of traditional Mass communities are not in communion with the Holy See. These are those who deny that the popes since Pius XII or at least the present or the last two popes were not truly popes. They are called “Sedevacantists.” Among them is the Society of St. Pius V.
The Society of St. Pius X (not to be confused with the ones just mentioned) are in some places fully legitimate (in the Archdiocese of Buenos Aires in Argentina), but everywhere they are in an imperfect but real communion with the Holy See, since they recognize the pope and have received faculties from him for the hearing of confessions. All of these groups have valid Masses, even if they are not in communion with the Holy See.
You should note, however, that “Latin Mass” is not synonymous with the traditional, or Tridentine, or Extraordinary form of the Mass. The “New Mass” is also celebrated in many places in Latin. Latin is the liturgical language of both the old and the new rites.