Society is becoming increasingly globalized with every year. Meanwhile, most of SEO is highly anglocentric. Almost everything discusses how to optimize an English site for American audiences, or at most, audiences spanning the United States, Canada, the United Kingdom and Australia. The rest of the world is forced to sit in a corner and watch.
Meanwhile, the United States and the rest of those English-speaking countries are growing less and less English-dominant. English isn't even officially the American language. Communities rise up within cities with bilingual capability, or even dominant non-English languages. Detroit has significant Arabic-speaking populations. Chicago is full of Polish-speaking households. Seattle is packed with Japanese speakers. New England is full of Chinese.
All this means that small businesses can benefit from implementing bilingual websites for local areas.
Then you have the idea of border towns. Businesses along the US-Mexico border can often benefit from bilingual English-Spanish websites. After all, much of their clientele may be Hispanic or Latino. On the northern border, you can see the same thing with Canadian French.
Then you step up, and you find companies participating on a global stage. We often advise marketers to block non-English countries from their targeting, but some businesses can take advantage of these audiences instead. Why block India when you can sell your product in Dubai, just by using a bilingual site?
Of course, then you have the global companies, companies that use one site for worldwide information and support, offering translations in dozens of languages. Many tech companies fall in this category.
So how do you implement bilingual support without jeopardizing your SEO?
Geotarget via URL
Google finds it difficult to determine the geotargeting of a page just by the content in many cases. Rather than attempt to spam language or region-focused keywords in you content, separate each language version in your site structure. You might have www.example.com/en/page1 and www.example.com/sp/page1 for English and Spanish versions. Or you might have www.example.com and www.example.fr, for English and French versions of your site.
Implement Meta References
Google can help you serve the right language to the right people based on region. You do this by using the rel="alternate" tag in conjunction with the hreflang tag to specify a language. Google can teach you more.
This also helps with any potential duplicate content issues, which can come up when translating content from one language to another.
User Agent Detection
You can detect the IP and user agent a user is browsing from, in order to serve the right content to them. This mostly works with multiregional SEO, but can also be used if a given user is browsing from an alternate language version of a web browser. This isn't flawless, however, so you can't rely on it to automatically detect user language preference.
Test Regional Variations
When you're implementing scripts to detect region or user agent and serve the appropriate regional content, it can be useful to use a proxy server to spoof your IP.
"If you're trying to serve regional content to an audience, forcing your connection to come from that region is a perfect way to test your scripts." said Dave Morris, CTO of GhostProxies. "There are a number of ways that you can accomplish this, like using proxies or VPNs to change your region."
If you're not trying to use automatic scripts, you still need to test that your alternate language site variants still work. If users in Japan were still viewing the English version of your site, for example, that wouldn't be very good user experience.
Be Wary of Translation
In every case, when you're implementing a multilingual site, you need to have someone qualified as a translator working for your content production team. Simply running a post through Google Translate won't work, and opens you up to all kinds of issues. Never try to implement a multilingual site without a qualified translation.
A properly implemented multi-regional or multilingual site will open you up to an entirely new audience, but you have to make sure it works.