What is good? Different website for different languaze or a multilinguist website is better idea!!
If you've enough time to market your each website, than I would suggest to use different website for each languaze. It will also help you to build and grow your local market too.You need enough content in different languaze to market your websites. You can't use same content for every website by only translating it to your desire languaze. It's simply called duplicating the contents, a unprofessional way to market your website.
It's also help you to minimize your website on-page and on-site issues. With a Multilinguist website you can't fix all the technical error as few of them are really helpful. Mark up validation may show you numbers of error, however it's not a ringing bell.
The next factor is linking; what strategy you need to follow to build your links? You've a non-English site and you're targeting the SE's based on the region, only because you've used specific languaze to reach your target audience. You can develop different contents to generate the links and specially you need anchor text with specific languaze. This'll reduce your campaign time limit.
Considering the languaze, you can target the keywords. I mean, this is really wise to target the local keywords to market your offerings. You can't go for only English keywords, when you've a non-English website.
Hence, I'll recommend to use different website for different languaze only when you've enough time to market it.
