Launchpad currently recommends translating synaptic in Ubuntu Cosmic.

Template "synaptic" in Ubuntu Cosmic package "synaptic"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 739 739 0 0
Dakota 100.00  100.0% untranslated 739 739 0 0
Hawaiian 100.00  100.0% untranslated 739 739 0 0
Inuktitut 100.00  100.0% untranslated 739 739 0 0
Lakota 100.00  100.0% untranslated 739 739 0 0
Ojibwe 100.00  100.0% untranslated 739 739 0 0
Spanish 000.00  100.0% translated 0 46 46 0 2018-03-30 07:42:29 UTC 2018-03-30 Paco Molinero
Tlingit 100.00  100.0% untranslated 739 739 0 0
Yiddish 100.00  100.0% untranslated 739 739 0 0
[ Change your preferred languages... View template & all languages... ]

Template "synaptic-manual" in Ubuntu Cosmic package "synaptic"

Language Status Untranslated Need review Changed Last Edited By
Cherokee 100.00  100.0% untranslated 360 360 0 0
Dakota 100.00  100.0% untranslated 360 360 0 0
Hawaiian 100.00  100.0% untranslated 360 360 0 0
Inuktitut 100.00  100.0% untranslated 360 360 0 0
Lakota 100.00  100.0% untranslated 360 360 0 0
Ojibwe 100.00  100.0% untranslated 360 360 0 0
Spanish 000.00  100.0% translated 0 118 118 0 2018-03-29 19:43:33 UTC 2018-03-29 Adolfo Jayme
Tlingit 100.00  100.0% untranslated 360 360 0 0
Yiddish 100.00  100.0% untranslated 360 360 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 synaptic in Ubuntu