Here is a nice Wikipedia definition of Surtitles:
Surtitles, also known as supertitles, are translated or transcribed lyrics projected above a stage or displayed on a screen, commonly used in opera or other musical performances…
Surtitles are used either to translate the meaning of the lyrics into the audience’s language, or to transcribe lyrics that may be difficult to understand in the sung form. The two possible types of presentation of surtitles are as projected text, or as the electronic libretto system. Titles in the theatre have proven a commercial success in areas such as opera, and are finding increased use for allowing hearing impaired patrons to enjoy theatre productions more fully. Surtitles are used in live productions in the same way as subtitles are used in movie and television productions
Supertitles are used in live professional productions when the performances are in a foreign language. An English translation of the words is projected above the stage
For the benefit of audiences of Opera by Children, we will provide for all teachers whose music we have arranged, a Power Point Slide Presentation with the surtitles/supertitles for your opera.
If you want more information about how they will be done, please contact Nellie Horrocks firstname.lastname@example.org
Education Director, Utah Festival Opera