Hello. I submitted a new translation today, with many changes (issue n° 5603:
http://ufoai.org/bugs/ufoalieninvasion/issues/5603). Here is a summary (cosmetic changes, typos and long rewrinting not included).
a) Many changes based on Rodmar's proposals (cf. his .po file). Examples : "Esprit" -> "Mental" ("Mind" in english), "Rafale de N coups" -> "Rafale de N", "Tir rapide" -> "Tir instinctif", "Tir ... retardé" -> "Tir ... à temps", "Coque" -> "Blindage", english "Coilgun" -> "Fusil à induction" (changed my mind here), english "Tolerant" -> "Attentiste", "Chargeur de lance-aiguille" -> "Chargeur d'aiguilles", "se dirige vers une mission" -> "en opération", "Tour radar" -> "Station radar", etc. I also reverted many "alien" into "extraterrestre" or "envahisseur".
b) Many changes to shorten the texts (greatly improves the display in the graphical interface) and to be more accurate. Examples: "Entrepôt à antimatière" -> "Cuve à antimatière" (I really hesitated with "Chambre à ...", but I think "Cuve" is good), "Centrale électrique" -> "Réacteur" (to comply with Rodmar's proposal "Arrêter le réacteur"), etc.
c) Few elements renamed, to shorten their names to improve display or accuracy. Main examples: "Centre de commandement" -> "Salle des opérations", "Quartiers d'habitation" -> "Caserne", "Inferno" -> "Brasier", "Entrepôt à OVNI" -> "Parc à OVNI", and "Épée à plasma" -> "Broche à plasma" (I really never liked "Épée" because this is obviously not a sword, but something to pin and burn people painfully; thus, "Broche" adds something brutal, turning victims into simple dead meat).
d) Uppercase labels turned into lowercase: in many occasion, uppercase labels were too long and did not display well (like "Télécharger", "Personnaliser", or even the name of the game, "UFO:Alien Invasion - with uppercase, the last N was nearly truncated over the main menu -, etc.)
EDIT (18/09/2016):
An updated .po file was added to issue 5603. The reason is...
e) "orbitron-medium" and "orbitron-light" polices translated into "DejaVuSans" police: better displayed of diacritics (é, É, è, È,à , À, etc.), and special letters and signs (œ, Œ, «, », etc.). Less truncated captions in dialog boxes (ex.: connexion dialog => with orbitron : « mot de pas... » ; with DejaVu Sans : « mot de passe »).