The psionic power mindlink does exactly what you want: It's low level and works on any creature that has an Intelligence of 3 or higher. (As long as you spend the points to make it work on an unwilling target.)
And most importantly:
You can communicate telepathically through the bond even if you do not share a common language.
As a backup option, as long as you can touch the ice toad, you can cast tongues on it. Tongues doesn't require a willing creature, so as long as the ice toad fails its will save this should allow it to speak to and understand you.
This spell grants the creature touched the ability to speak and understand the language of any intelligent creature, whether it is a racial tongue or a regional dialect. The subject can speak only one language at a time, although it may be able to understand several languages.
This won't allow it to speak to other ice toads:
Tongues does not enable the subject to speak with creatures who don’t speak.
So if you want it to be able to speak to other ice toads, you'll have to cast the spell on them too.
There is one other fly in this ointment:
The subject can make itself understood as far as its voice carries.
This is potentially problematic, because if ice toads don't have a voice (which may or may not be the case), they will be able to understand you but not speak loud enough for you to hear. This will enable any communication method that relies on the creature understanding you, and might allow communication methods that rely on the creature having a language. (Depending on whether understanding every language counts as "having a language"; I can't find a rules definition of what that requirement actually entails.)
Alternatively, with one-way communication established, you may be able to talk it into accepting a telepathic bond or some other method that relies on having a willing target.
From my knowledge there is no such language. Angels have this ability, but the languages they speak (Celestian and a few others) are just ordinary languages with no special properties. It's a supernatural ability of theirs which gives them a cheat mode:
In both games that ability takes the following form:
All angels can speak with any creature that has a language, as though using a tongues spell (caster level equal to angel’s Hit Dice). This ability is always active.
The Tongues spell this ability refers to is also identical in both games (D&D 3.x Tongues and Pathfinder Tongues):
This spell grants the creature touched the ability to speak and understand the language of any intelligent creature (snip)
So: there's no cheat-mode language for mortals to learn. They just need to have Tongues. If they're using that spell, they follow its rules and can understand and speak other languages.
Best Answer
Monk is the Way
I did not see anything in your initial question that would prohibit it, but a 13th level Monk with the Tongue of the Sun and Moon trait would meet two-thirds of your criteria very well (being able to understand and speak all spoken languages).
The final third (being able to read all spoken languages) can be easily accomplished by a 1 level dip into Bard or Wizard; taking the Comprehend Languages spells; and using the innate Ritual Casting ability of those classes to cast the spell.
Alternately, you can simply have your Monk take the Ritual Caster feat and pick one of those classes for it.
One other thing you could do to gain Comprehend Languages is find a Helm of Comprehending Languages, which will permit you to cast the spell at-will. As an uncommon magic item, this may be very achievable in certain settings.