first things first, regarding working in Germany.
1. you are not allowed to just obtain an employment as a Malaysian (unlike foreigners from the EU). Therefore, your employer has to apply a migration and work permit for you. There is a fast track called Blue Card for tech related employments (engineering, IT, etc) which require a minimum gross salary of EUR 43.000 (~200k RM) p.a. I can't say for sure if being a tax consultant qualifies for that.
2. You are not allowed to work as a tax consultant. At least not for German tax laws, as the job of a tax consultant is a so called restricted job that requires a specific license. That test is known as one of the most difficult professional tests you can do in Germany at all, as the tax law is way more difficult compared to Malaysia or the UK. Second of all, you have to take it in German and with mandatory studies and apprenticeship, we are looking for at least 5 years before you would be eligible to work as a registered tax consultant. BUT, you can work as a consultant on foreign taxation (sounds similar, but it isn't) under the umbrella of a registered tax consulting company.
3. Even practicing German in Germany as a foreigner isn't that easy. As you would tend to move to one of the larger cities (Berlin, Hamburg, Frankfurt, Munich), English is pretty common nowadays. I can't refer to a language center, but I would recommend to join expat groups on facebook and ask for any tutoring by one of the expat wives. Most of them aren't working and often have a professional background.