1. A speech learning apparatus comprising: a detection unit configured to detect a keyword corresponding to a character string selected from text by a user using a marker; a first calculation unit configured to calculate a score indicating a degree of emphasis of the keyword based on a type of the marker and a manner of selecting the keyword; a generation unit configured to generate a synthesis parameter to determine a degree of reading of the keyword in accordance with the score and the type of the marker; an addition unit configured to add to the keyword a tag for reading the keyword in accordance with the synthesis parameter; and a speech synthesis unit configured to generate synthesized speech obtained by synthesizing speech of the keyword in accordance with the tag.