Dr. Matilda “Tilly” Foster

Dr. Matilda Foster (known as "Tilly" to most of the people she worked with) was a Doctor of Xenolinguistics.
=== Reaper War ===
Tilly had been the top Prothean scholar at Macquarie University, and had been in the midst of revamping their curriculum to include the languages of the more minor "client races" of the Prothean Empire instead of only studying the Imperial variant. 
The young doctor had been trapped on the university when the Reapers hit, and took refuge in the campus' sub-basements. To drown out the screams and other sounds of battle, she spent her time reciting conjugation tables and morphological theoretics under her breath, and re-reading the Prothean literature on her omni-tool. Though she survived the war, she quite understandably struggles with profound PTSD.
=== Every One That Asketh ===
Though her therapist had suggested that she discontinue studying language (at least until she could get her flashbacks under control), when the resistance began looking for anyone who could assist in translating information in the Mars Prothean Archives Tilly immediately volunteered. On September 23, 2188 she and one of her research partners received a shocking visitor- Javik, Avatar of Vengeance. Tilly's fluency in Imperial Prothean and understanding of his culture impressed the prothean general- and perhaps her gumption in demanding some kind of respect. He agreed that a discussion of what they found would be far less tiresome than simply translating.