A simple, normal API like: send a CURL to this endpoint with those parameters and that secret key, here's your response, have fun?
Something that does not require you to include their huge crazy cloud SDK that is dependent on tons of other third party libraries?
Google offers a Cloud Translation API to which you send simple CURL request with parameters and get back JSON response.
Without Cloud SDK installed you can use curl command like this:
curl -k "https://translation.googleapis.com/language/translate/v2?q=Hello+World&target=de&key=<API_Key>"
Required parameters are:
You can also use Cloud Translation API Client Libraries with your language of choice.
If having Cloud SDK installed is not an issue, you can follow a quickstart guide to get you started.