Files with .18 extension are used by VoiceType software application developed by IBM. VoiceType is a speech recognition and transcription software. Files with .18 extension contain data that support speech recognition process.

VoiceType debuted in 1997 and after some improvements and updated was renamed IBM ViaVoice. One of its distinct features is the ability to learn users’ speech and intonation patterns. ViaVoice was a solid solution for its time, but soon began to be displaced from the market by more advanced tools based on Artificial Intelligence.