It would be good to have a context menu when in a party or team.... quick sound / (visual cues if the avatar does not disappear :-) ) it will help assist quick language cues/references.
By universal language i though this was already defined by devs as being an english based game, referencing the business language used in the world today.
Anyway that aside even If there is a language barrier it also opens up job roles for proxy/ trade or communication professionals, or those natural diplomats who like to be mediators or can speak/understand both sides.
In summary, a vocal cue context menu would be good to have in certain situations. Parties or squads may only require simple actions and cues to issue and aknowledge or the activites or understood actions were simple and pre-agreed on.
Chat boxes should be present or have separators or tabs for the types of chat (or something like it for: squad, Org / alliance, local area (5 hex tiles) and whisper chat.
I think GLOBAL chat should be hidden bar server announcments, to encourage org communication to known what is happening outside and for the clever....well they could take advantage of this in the form of jobs or bulletins in game.
VOIP it is a great option whilst not in game, discord is handling it nicely, in a round about sense. ie to chat you have to be in the same org and voice channel to chat....though to fix this simply have a communal or gathering area to go to. So to VOIP with someone you only have to meet up and invite them.