The Devon and Cornwall Police website has information on how to make a silent 999 call, although they do not recommend this as it is not always possible to locate someone accurately or quickly.
If you are experiencing domestic abuse, there is help available from people who understand what you are going through and who won't blame or judge you. Standard services will support you, but can also find you specialist support if you prefer for example because of your ethnicity or sexual orientation. Domestic abuse and sexual violence can happen to anyone. If it's happening to you, please tell someone.
This website should translate into the language which your browser usually uses. If not, Women's Aid have produced some information and advice in 15 different languages. These were produced in May 2020 in response to the lockdown restrictions during the COVID-19 pandemic, but the wider information will be relevant at any time.