Safer than most other areas because of a Muslim ethic and intact social fabric. Keep safe by making friends. The Minang take great community responsibility. Talk to people and they will look out for you as one of their own. At the same time crime exists and normal precautions should be taken. Importantly, respect their values and, if female, try not to travel alone after dark--in company with other women is OK. The ethos - the community can't look after you if you don't look after yourself. Or if you go places where the honest eyes can't see. So being alone or the only female in male company at night is considered asking for it.
talk
Most people in West Sumatra uses Minang language in their daily conversation. It's somewhat similar to Malay language, due to the fact that Melayu language is the origin root of both languages.