Thank you for the screenshots... very easy to understand!

I forgot to include those translations. I am working on it right now. 

I'm curious... are these translations from Google really bad?

Ticket Number
Last Updated
Subject
From
Assigned To
Due Date
Close Date
Date Created
Department
Last Message
Last Response
Status
Team

Ticketnummer
Letzte Aktualisierung
Gegenstand
Von
Zugewiesen an
Geburtstermin
Abschlussdatum
Datum erstellt
Abteilung
Letzte Nachricht
Letzte Antwort
Status
Mannschaft

I'll have a patch ready tonight or tomorrow with all languages. But if you want a quick fix for German you can add the following to /osta/user-styles.css:

html[lang="de"] .list td.osta_ticket:before { content: "Ticketnummer";}
html[lang="de"] .list td.osta_lastupdated:before { content: "Letzte Aktualisierung";}
html[lang="de"] .list td.osta_subject:before { content: "Gegenstand";}
html[lang="de"] .list td.osta_username:before { content: "Von";}
html[lang="de"] .list td.osta_assignee:before { content: "Zugewiesen an";}
html[lang="de"] .list td.osta_duedate:before { content: "Geburtstermin";}
html[lang="de"] .list td.osta_closedate:before { content: "Abschlussdatum";}
html[lang="de"] .list td.osta_datecreated:before { content: "Datum erstellt";}
html[lang="de"] .list td.osta_department:before { content: "Abteilung";}
html[lang="de"] .list td.osta_lastmessage:before { content: "Letzte Nachricht";}
html[lang="de"] .list td.osta_lastresponse:before { content: "Letzte Antwort";}
html[lang="de"] .list td.osta_status:before { content: "Status";}
html[lang="de"] .list td.osta_team:before { content: "Mannschaft";}

Ticketnummer<br />
Letzte Aktualisierung<br />
Gegenstand Betreff<br />
Von<br />
Zugewiesen an<br />
Geburtstermin (that would be the predicted day of baby birth) Fällig am / Fälligkeitsdatum<br />
Abschlussdatum (would be technically ok, better is:) Geschlossen am / Schließdatum<br />
Datum erstellt (would be technically ok, better is:) Erstellt am / Erstelldatum<br />
Abteilung<br />
Letzte Nachricht<br />
Letzte Antwort<br />
Status<br />
Mannschaft Team is fine