"I'm trying to get signal on my phone" or "I'm trying to get Signal on my phone". Great(!)
The name was changed after Whisper was launched https://whisper.sh/
IronChatApp.com is available. ("Steel"|"Lock"|"Forti"|<anything that conveys security>) + ("Chat"|"Talk"|...).
I'm not sure, there are tons of professional marketing/branding/PR firms who do this really well. TextSecure et al were acquired, IIRC. If the parent company has 50k to throw around, approaching W+K might be a good investment.
Edit: Mea culpa. It was WhisperSystems not OpenWhisperSystems which was acquired, both of which were founded by Marlinspike. This, incidentally, proves my point that naming similarities (WS vs OpenWS) within a similar domain (both mentally associated as "moxie" projects in my mind, in this case) can lead to problems.
No, moxie's previous company (Whisper Systems) was acquired by Twitter (iirc), Open Whisper Systems is a different project. See https://en.m.wikipedia.org/wiki/Open_Whisper_Systems and https://en.m.wikipedia.org/wiki/Whisper_Systems
Bosnian (Latin): signala
Bulgarian: сигнал
Catalan: senyal
Croatian: signala
Czech: signál
Danish: signal
Dutch: signaal
Estonian: signaali
Finnish: signaali
French: signal
German: Signal
Indonesian: sinyal
Italian: segnale
Latvian: signāls
Lithuanian: signalas
Yucatec Maya: señal
Norwegian: signalet
Querétaro Otomi: señal
Polish: sygnał
Portuguese: sinal
Russian: сигнал
Serbian (Latin): signal
Slovak: signál
Slovenian: signala
Spanish: señal
Swedish: signal
Ukrainian: сигнал
Welsh: signal