When the enterprise grows to have a global reach, exactly how the overall web presence is managed becomes a concern for search compliance. Lack of attention to this can result in domain level redundancies triggered by multiple sites sharing common content, functionality, and other assets. Before you propagate foreign language sites make sure the consequences are understood from a compliance viewpoint. Basically you want to reduce the impact of those sites on the mother ship in the primary search, while enabling each site in each country to rank within their geo area, where it is much easier to attain high ranks.
One Site Per Language
You CANNOT clone your US site in another English speaking country, and expect to rank both. This can eventually result in a penalty on the most valuable property, since the second English language site will be seen as an attempt to spam the system with duplicate content for a ranking edge. Additional English language sites require UNIQUE content, AND no robot detectable connection to the main enterprise. Remember, Google has a guideline requiring each enterprise to be represented by only ONE website. Of course you can have more, but they must be implemented compliantly, meaning that ownership of both cannot be detected by a visiting robot.
Foreign Language Sites : Their Edge
Because of the semantic nature of the search, different languages keep sites with the same, but translated content, from being redundant with one another. Of course, all other compliance requirements are in effect, so this site can rank, on its own, in its geo segmented market. Ranking sites in foreign versions of Google is much easier, and large sites have a distinct advantage.
Foreign Language Sites : Common Problems
Assuming your translation is not an issue, the most common problems faced by foreign language sites relate to their autonomy.
It is not recommended that you share web assets with any other site in the enterprise, unless natural search ranks don't matter. This is a very common problem, because the developers of your sites are looking for efficiencies. They will often make one version, say a form, post it in once place, and the share it across all the sites by referencing the one file. Sharing assets does save work, and managers will always agree to the most efficient allocation of resources. But there are search consequences to implementations that reveal ownership relationships. Especially if the enterprise oversees multiple sites with valuable overlapping target terms. You can't be seen to have more than one horse in each horse race. And sharing a file from one location across all the foreign sites is telling Google something you want to keep to yourself. This is one very good example of how a compliance mandate can save the enterprise a huge rank loss headache.
Within one organization, the control of the foreign language sites may be handled locally or centrally. The latter is obviously easier to oversee for compliance. Locally managed sites that tap shared web assets need to be vetted for compliance from a central authority for reasons stated above. If the foreign sites are separate domains, or subdomains, make them as completely autonomous as possible. Let there be no robot detectable connection that reveals ownership.
And if you oversee an enterprise with many foreign language sites, you need to consider how the interconnectivity of your sites is impacting the ability of each site to rank. If you're looking at interlinked sites, and poor ranks, you might want to conduct a compliance review.