Re: Azorean Translator Earbud
1) You want to be building this out of plastics. Titanium expands when it grows cold and leaves "burns" if it's against your skin for prolonged periods (this is why you never see titanium jewelry but you do see titanium alloys).
It is however, highly resilient to corrosion, very light and quite strong so it might be ideal provided you use like an aluminum/plastic based paint over it.
A lot of people think titanium is super strong but in truth, it's probably only 4 times stronger than most common composite iron alloys. The real strength is that for the same WEIGHT and SPACE it can be a lot stronger, it just has to be a lot denser.
2) It doesn't even need to be a complex computer with software and an operating system!
It could just be a neural gateway mechanism built out of cultured cells or well refined conductive crystal pathways, similar to integrated silicone circuits on chips that chemically shift.
How they're educated, however, would have to be very simple unless the device is a system that piggy-backs the neural work of the user using something like magnetones or binural beats and subliminal versing (bio-feedback). Scary.
3) Power source? The options are immense. The two particularly popular micro-power sources that are growing popular are chemical batteries (an issue, but with a restoration mechanism like heat & light, could be feasible for long-term) and nuclear. Nuclear does not constitute uranium specifically:
Hafnium is popular because if you apply a weak microwave charge, it becomes highly active, it's half-life moving from practically inert to about 7 minutes. The math says 60 grams could power a fighter-jet on the heat and electricity alone for about a week of combat performance so one gram would be more than ample for a life time's supply of electrical energy to something like that device if coupled with a capacitor or battery mechanism. Best of all, the halflife only applies to the atoms the microwaves actually reach, so if they're at the right frequency and weak, you can get a highly regulated and controlled decay, ideal for something like this.
Hafnium when not "activated" is so inert and safe, you can rub it into your skin and even eat it with no ill effects long-term provided no microwaves penetrate your skin to activate it. The only issue is it's expensive (ie, unperfected) but the technology is extremely efficient, requiring less energy to shift the half-life and make the stuff useful.
The real strength of Hafnium is it's losing electrons at a stable controllable rate so you can hook up electrodes to it and use it as a live battery (unlike Uranium, which is functional at all times and therefor quite dangerous and is only able to function as a battery cathode as Uranium Dioxide within the bounds of known science).
Sorry to scare you with this big wall of text :3