1. A speech learning apparatus comprising: a processor, programmed to detect a keyword corresponding to a character string selected from a text; calculate a score indicating a degree of emphasis of the keyword based on a manner of selecting the keyword; generate a synthesis parameter to determine a degree of reading of the keyword in accordance with the score; add to the keyword a tag for reading the keyword in accordance with the synthesis parameter; generate synthesized speech obtained by synthesizing speech of the keyword in accordance with the tag; calculate a social score indicating a score of the keyword selected by one or more other users different from the user; and calculate an integration score using the score and the social score, wherein the synthesis parameter is generated in accordance with the integration score.