asterisk-core-sounds-en binary package in Ubuntu Bionic amd64

 Asterisk is an Open Source PBX and telephony toolkit. It is, in a
 sense, middleware between Internet and telephony channels on the
 bottom, and Internet and telephony applications at the top.
 .
 Asterisk includes a set of standard sound files in various formats.
 The core part of that collection in US English, by voice actress
 Allison Smith, is contained in various encodings in packages
 asterisk-core-sounds-en-*; this package registers these through the
 alternatives system to provide the default "en" (English) and "en_US"
 (USA English) sounds.

Source package