Estimation method, recording medium, and estimation device

An estimation device that estimates an oral function or a cognitive function, the estimation device comprising:

• a first voice feature group obtainer that obtains a voice feature group of a plurality of persons who speak a first language, by analyzing voices obtained by prompting the plurality of persons who speak the first language to speak a first language sentence that is in the first language and is similar in pronunciation to a second language sentence spoken in a second language different from the first language;
• a second voice feature group obtainer that obtains a voice feature group of a plurality of persons who speak the second language, by analyzing voices obtained by prompting the plurality of persons who speak the second language to speak the second language sentence;
• a subject voice feature obtainer that obtains a voice feature of a subject who speaks the first language, by analyzing a voice obtained by prompting the subject to speak the first language sentence;
• a corrector that corrects the voice feature of the subject according to a relationship between the voice feature group of the plurality of persons who speak the first language and the voice feature group of the plurality of persons who speak the second language;
• an estimator that estimates, from the voice feature of the subject that has been corrected, an oral function or a cognitive function of the subject by using an estimation process for an oral function or a cognitive function based on the second language;
• and
• an outputter that outputs a result of estimation of the oral function or the cognitive function of the subject.