Launchpad currently recommends translating gdm3 in Ubuntu Cosmic.

Template "gdm" in Ubuntu Cosmic package "gdm3"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 88 88 0 0
Dakota 100.00  100.0% untranslated 88 88 0 0
Hawaiian 100.00  100.0% untranslated 88 88 0 0
Inuktitut 100.00  100.0% untranslated 88 88 0 0
Lakota 100.00  100.0% untranslated 88 88 0 0
Ojibwe 100.00  100.0% untranslated 88 88 0 0
Spanish 000.00  100.0% translated 0 0 2 2 2018-10-17 01:40:43 UTC 2018-10-17 Daniel Mustieles
Tlingit 100.00  100.0% untranslated 88 88 0 0
Yiddish 100.00  100.0% untranslated 88 88 0 0
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Template "patches" in Ubuntu Cosmic package "gdm3"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 6 6 0 0
Dakota 100.00  100.0% untranslated 6 6 0 0
Hawaiian 100.00  100.0% untranslated 6 6 0 0
Inuktitut 100.00  100.0% untranslated 6 6 0 0
Lakota 100.00  100.0% untranslated 6 6 0 0
Ojibwe 100.00  100.0% untranslated 6 6 0 0
Spanish 000.00  100.0% translated 0 0 0 2018-10-17 01:42:31 UTC 2018-10-17 Francisco Javier Cuadrado
Tlingit 100.00  100.0% untranslated 6 6 0 0
Yiddish 100.00  100.0% untranslated 6 6 0 0
[ Change your preferred languages... View template & all languages... ]
Key to this table: “Unchanged” means Translated
and “untranslated” means just that, Untranslated

Other versions of gdm3 in Ubuntu