Vortigaunt

I did not write this i got it from this website half-life.wikia.com/wiki/Vortigaunt

Physiology
In appearance, Vortigaunts are somewhat humanoid, with two legs and two arms and an additional third arm protruding from the chest. This extra limb is a feature also found in other bipedal, sapient species from Xen, including the Alien Grunt and the Nihilanth. This similarity, along with other shared features such as red eyes and back-jointed legs, is strongly suggestive of a common ancestry with other intelligent Xen life forms. Apparently, this third arm is used for feeding, as both Vortigaunts and Alien Grunts are often seen bending over slain victims, feeding on them.
Vortigaunts have mottled green-brown skin, sharp teeth, and clawed hands. Vortigaunts have a slightly hunched posture, and their faces are dominated by a large, single eye with a maroon sclera and a heterochromic red-yellow iris with a yellow pupil, surrounded by three smaller eyes. All four eyes are actually multiple openings to a single eye surface, as noted on a white board in Questionable Ethics. They also have a navel, two rectums, and four nipples, suggesting that Vortigaunts reproduce in a similar fashion to Earthly mammals.

Another interesting feature of the Vortigaunts is that they have no tongue or teeth on their lower jaw, yet they can speak English fluently, albeit with a strange accent and some sort of speech impediment when using S's and R's.

Intelligence and culture
Vortigaunts are very intelligent and social creatures. Throughout the Half-Life series, they can be seen in pairs or groups, and are capable of developing intelligent strategies. When faced with a superior enemy, Vortigaunts will often run away, and if possible, group together with other Vortigaunts to form a stronger force.[6]

Vortigaunts "communicating" over a corpse in Black Mesa's Lambda Complex.
Brief glimpses into the Vortigaunt culture can be gained by occasional speeches given by them in Half-Life 2, and in scenes during the original Half-Life. In the original game, Vortigaunts were enslaved by the Nihilanth and used as workers and drone soldiers, Based on comments by the All-Knowing Vortigaunt, it seems that the species has endured slavery for many generations ("We have endured these chafing bonds for eons, yet a single moment of further servitude seems intolerable!" as he says) and enforced servitude appears to have formed the bedrock of Vortigaunt history and culture up to the events of the first Half-Life. In Half-Life 2, Vortigaunts make occasional references to their species' culture.

Communication and the "Vortessence"
Vortigaunts possess their own native form of vocal communication, which, in Half-Life 2, is referred to as "flux shifting", and can be heard in rare instances when two Vortigaunts are engaged in conversation. According to the Vortigaunts, flux shifting cannot be understood by "those whose Vortal inputs are impaired", which may suggest that other inaudible components are involved, perhaps explaining why it is incomprehensible to humans.[3] One example of flux shifting occurs during the aftermath of the first Hunter attack in Half-Life 2: Episode Two, when the Vortigaunt that saves Alyx calls out over an immense distance to communicate with its kin, using two short but apparently highly descriptive calls.

By the beginning of Half-Life 2, Vortigaunts have learned to speak at least one human language, which, in the English language version of the game, is predictably English (in some international versions of Half-Life 2, Vortigaunts speak the appropriate language for the country of the game's release, e.g.: in the French language version of the game, the Vortigaunts speak French). However, when speaking English, Vortigaunts use archaic words and syntax, tending to use outdated, even Shakespearean phrases.

Vortigaunts also tend to refer to individuals by adding "the" before their name, such as "the Freeman" or "the Alyx Vance". This practice of adding definite articles before names is commonplace in some real-world languages, such as German. Thus, the argument stands that the Vortigaunts may have picked up this habit from learning a language like German, and then simply kept the habit when they learned English. Additionally, City 17 and the other areas explored in Half-Life 2 and its episodes are widely speculated to be somewhere in eastern Europe, and German may have been spoken in or near it before the Seven Hour War and the subsequent Combine takeover.

Vortigaunts believe in a binding life-force which they call the "Vortessence". Due to their use of this force, which remains untapped by humans ("We are a tapestry woven of Vortessence. It is the same for you if only you would see it.", as said by the All-Knowing Vortigaunt), the Vortigaunt species can communicate with one another telepathically. They believe Vortessence is the fabric of the universe, made of "vortal cords", of which everything is woven (and therefore everything is connected). The Vortigaunts are able to read and control this force for their electrical powers, nearly hive-mind telepathy and, likely, their ability to take power from objects. They can use their powers coupled with "the extract" of Antlion larvae to bring the dead back to life (however, it is shown in Episode Two that they cannot do this alone)

Better... But ughhh you know how I feel about the wiki.