When a person drinks the medicine, any words they shout or speak loudly will cause them to spew out a solid form of the sound. For say, if the person shouted 'Ya!', a corresponding Katakana letter 'Ya' (ヤ) will come out. Meanwhile, İf user shouts 'Ro' it will became a object shaped like "ロ". The shouted letter will fly in accordance of the shouter's direction. The letter's velocity is slightly slower than sound, and it does bounce off or be absorbed into hard surfaces and soft surfaces respectively(because their properties is rather similar to sound). The letters can be ride on, but varying on what type of letter it is, how well it can be a mode of transportation also varies.
- Flying Through the Sky on the Letter "ワ"
- Move Fast, Doraemon! The Galactic Grandprix
- Doraemon: Nobita and the Island of Miracles ~Animal Adventure~
- So far, the Sound Medicine makes the user shouts out solid Katakana letters, the medicine is probably made that way.
- Mostly used characters are Wa ' ワ' and Ro 'ロ'.
- According to Doraemon in the 1979 anime, Voice Thickener is not bitter or spicy.
- In the 1979 anime, the effect lasts for 30 minutes, but in the 2005 anime, it lasts for a long time.
- Its Japanese name 'コエカタマリン' is possibly derived from 'コエ' (Sound) and 'カタマラ' (Harden).