The bard's bardic performances say nothing about concentrating and only a handful mandate Perform skill checks (countersong, distraction, et al.), making the others possibly usable while in a rage. However, performances do require using some kind of action to start and, often, to maintain. So while it's totally legit to get really angry and, for example, climb a mountain or swim a channel, because bardic performances use actions, starting or maintaining them while in a rage might run afoul of this part of the rage description:
While in rage, a barbarian cannot use any Charisma-, Dexterity-, or Intelligence-based skills (except Acrobatics, Fly, Intimidate, and Ride) or any ability that requires patience or concentration.
Emphasis mine. So while the barbarian's rage itself doesn't explicitly forbid, for example, massive shredding on your lute or belting out "99 Bottles of Dwarven Ale on the Wall" while simultaneously furiously headbutting orcs to death, the GM can simply say No, starting and maintaining a bardic performance requires patience that's impossible while raging.
This GM would allow a character in a rage to start or continue an appropriate bardic performance
The player should be aware that it's a tough row to hoe, though. In addition to other issues like multiple ability score dependency,1 the huge—perhaps, I dare say, insurmountable—problem with playing, for example, a barbarian 3/bard 4 is that such a character will each day have only a total of 11 rounds of fight in him (and that's generously assuming a Con 16 and Cha 16).2 Level 7 is actually past the point when the wizard can cast an extended rope trick and everybody can rest in the extradimensional space in relative safety, so being good for only two fights per day (unless the group's really efficient) is fine at that point, but actually playing this character to that point would be a constant and—for me, anyway,—unpleasant war with an ever-ticking clock.
1 Such a character needs high Str, Con, and Cha, would like a high Dex and Int, and will regret a low Wis.
2 Yes, I'd put the extra level in bard. That means 2nd-level bard spells.
- I'm sure I've seen it before but cant find it, but what counts as an intelligent creature?
Any creature with an intelligence score.
The Intelligence section of the Ability Scores chapter clarifies that:
Intelligence determines how well your character learns and reasons. This ability is important for wizards because it affects their spellcasting ability in many ways. Creatures of animal-level instinct have Intelligence scores of 1 or 2. Any creature capable of understanding speech has a score of at least 3. A character with an Intelligence score of 0 is comatose. Some creatures do not possess an Intelligence score. Their modifier is +0 for any Intelligence-based skills or checks.
I bolded the part that should interest you more. That section also gives a a couple of exceptions for creatures with no intelligence score:
Animals have Intelligence scores of 1 or 2 (no creature with an Intelligence score of 3 or higher can be an animal).
Oozes do not have an Intelligence score, and as such they have immunity to all mind-affecting effects (charms, compulsions, phantasms, patterns, and morale effects). An ooze with an Intelligence score loses this trait.
Regular plants, such as one finds growing in gardens and fields, lack Intelligence, Wisdom, and Charisma scores; even though plants are alive, they are objects, not creatures.
Vermin do not have an Intelligence score, and as such they have immunity to all mind-affecting effects (charms, compulsions, morale effects, patterns, and phantasms). Mindless creatures have no feats or skills. A vermin-like creature with an Intelligence score is usually either an animal or a magical beast, depending on its other abilities.
And the int score table gives us three examples of creatures that do not have an Intelligence score (their Intelligence is "-"):
Zombie, golem, ochre jelly
The Animal subtype also confirms that a creature with 3 or more intelligence is not an animal. But be careful to not confuse that with animal companions with high int scores.
Now, we also know that animals can be trained, and even learn how to understand speech (with ranks on Linguistics). But most animals cannot speak unless you get them a Circlet of Speaking.
Tongues does not enable the subject to speak with creatures who don't speak.
This clause on the spell description is the only thing that prevents the spell from being used to understand animals, so we have to use Speak with Animals instead.
- Can I cast the spell on myself and speak with every summoned creature (provided it counts as intelligent)?
Yes.
You are satisfying all the requeriments for the spell to work.
- If that does not work, can I cast this spell on my summons so they can understand me, as the spell doesn't say the target must be intelligent?
Yes.
However, the spell says your target can understand speech, but does not say they acquire the necessary intelligence score to follow and rationalize whatever is told him.
They will be limited by their own intelligence score. So an animal will understand "danger", "hunger" or "help", but will not understand "what direction did the bandit go?", because that is probably too much for their limited intelligence.
Score Examples Description
-: Zombie, golem, ochre jelly
0: Comatose
1: Carrion crawler, purple worm, camel Lives by the most basic instincts, not capable of logic or reason
2-3: Tiger, hydra, dog, horse Animal-level intelligence, acts mostly on instinct but can be trained
4–5: Otyugh, griffon, displacer beast Can speak but is apt to react instinctively and impulsively, sometimes resorts to charades to express thoughts
6–7: Troll, hell hound, ogre, yrthak Dull-witted or slow, often misuses and mispronounces words
8–9: Troglodyte, centaur, gnoll Has trouble following trains of thought, forgets most unimportant things
10–11: Human, bugbear, wight, night hag Knows what they need to know to get by
Best Answer
You are right that the key word here is "communicate," but unfortunately, because that word has no specially-chosen meaning in the RAW,
The answer varies depending on the creature summoned, and may not be covered clearly by RAW alone.
However, here are cases clearly covered by the RAW:
The GM's intepretation of the RAW may permit other options:
I don't mention the Charisma check as a joke: Simple commands like "Attack that guy" can be implied well enough with two or three words and some pointing. Anybody can memorize two or three key phrases in several different languages. But that kind of thing is subject to GM interpretation.