return search results in different languages

I don't know how your module uses the this module, but the geonames module simply wraps results returned by the geonames.org webservices. By default, in the case of search:

$query = array('query' => 'konstanz');
$results = geonames_query('search', $query);
print_r($results);

We just get back structured data straight for the service:

...
    [results] => Array
        (
            [0] => Array
                (
                    [name] => Konstanz
                    [lat] => 47.6666667
                    [lng] => 9.1833333
                    [geonameid] => 2885679
                    [countrycode] => DE
                    [fcl] => P
                    [fcode] => PPL
                    [distance] => 
                )

        )
...

According to the geonames documentation for the "search" service at http://www.geonames.org/export/geonames-search.html - you can pass a language parameter:

lang
string ISO-636 2-letter language code; en,de,fr,it,es,... (optional)
place name and country name will be returned in the specified language. Default is English. Feature classes and codes are only available in English and Bulgarian. Any help in translating is welcome.

So using PHP like:

$query = array('query' => 'konstanz', 'lang' => 'de');
$results = geonames_query('search', $query);
print_r($results);

I this case, the result is exactly the same as above. Perhaps your integration is using the "get" service to get more information about the results? Again, you can use that with the "lang" parameter:

$query = array('geonameid' => $results->results[0]['geonameid'], 'lang' => 'de');
$one = geonames_query('get', $query);
print_r($one);

delivering a result like:

...
    [results] => Array
        (
            [0] => Array
                (
                    [name] => Konstanz
                    [lat] => 47.6666667
                    [lng] => 9.1833333
                    [geonameid] => 2885679
                    [countrycode] => DE
                    [countryname] => Deutschland
                    [fcl] => P
                    [fcode] => PPL
                    [fclname] => city, village,...
                    [fcodename] => populated place
                    [population] => 81275
                    [alternatenames] => Constanca,Constance,Constanta,Constanza,Constança,Constanţa,Costanza,Konstancja,Konstanz,Kostnice,קונסטנץ,コンスタンツ,康斯坦茨
                    [elevation] => 
                    [continentcode] => EU
                    [admincode1] => 01
                    [adminname1] => südwestdeutschland
                    [admincode2] => 
                    [adminname2] => 
                    [alternatename] => 康斯坦茨
                    [timezone] => Europe/Berlin
                )

        )
...

Hope this helps. If it does, please close this issue.