What are some alternatives?
When comparing Signal and Telegram, you can also consider the following products
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Slack - A messaging app for teams who see through the Earth!
Riot.im - Open source interoperable collaboration app.
Tox - Send messages, files, create groups and make Tox to Tox audio and video calls. Securely.
Skype - Stay in touch with your family and friends for free on Skype. Download Skype today to chat and call on desktop and mobile.
Wire - Private & Secure Messenger