/translate, in FFXI, was usually just used to add items into your auto-translate list. Since the game only stores 200 items max (I think FFXIV stores even less), once that list is full you can't simply just view an item and have it added to it.

Currently, if your list is full, you have to shut the game down completely, re-log, then view the item to have it added to the list. The problem is, even after doing this they don't stay in the list for the remainder of your play session. Rewards from leves, quests and possibly synthesized items and repairs overwrite items already in your list.

So if you're trying to sell or buy something through shout but are constantly doing stuff in game between shouts, whatever it is will eventually be removed from the list, forcing you to re-log to add it again.