The first two types of Buddha both achieve Nirvana through their own efforts, without a teacher to point out the Dharma. The term Savakabuddha does not occur in the Theravadin Pali Canon, but is mentioned in three Theravadin commentarial works, and in the Tibetan tradition, and refers to an enlightened disciple of the Buddha.
Three variations can be distinguished in the way of achieving Samyaksambuddha-hood. With more wisdom (prajñādhika), with more effort (vīryādhika) or with more faith (śraddhādhika). Śākyamuni was a Prajñādhika (through more wisdom) Buddha. The next Buddha of this world, Maitreya (Pāli: Metteyya) will be a Vīryādhika (through more effort) Buddha.
In some works they are referred to as "silent Buddhas". Several comparatively new Buddhist scriptures (of later origin; after the Buddha's demise, like the Jātakas), show Pratyekabuddhas giving teachings. A Paccekabuddha can sometimes teach and admonish people, but these admonitions are only in reference to good and proper conduct (abhisamācārikasikkhā), not concerning Nirvana.
In some texts, they are described as 'one who understands the Dharma by his own efforts, but does not obtain omniscience nor mastery over the Fruits' (phalesu vasībhāvam).
Enlightened disciples attain Nirvana as do the two aforementioned types of Buddhas. After attaining enlightenment, disciples may also lead others to enlightenment. One can not become a disciple of a Buddha in a time or world where the teaching of the Buddha has been forgotten or has not been taught before, because this type of enlightenment is dependent on a tradition that stretches back to a Samyaksambuddha.
A rarely used word, anubuddha, was a term used by the Buddha in the Khuddakapatha for those who become buddhas after being given instruction.
The types of Buddha do not correspond to a different Dharma or truth; the truth discovered by them is one and the same. The distinctions are based solely on issues concerning studying and teaching. If one has a teacher who points out the Dharma and one realises this Dharma for oneself also, one is an Arahant (Śrāvaka). If one discovers the Dharma without a teacher, and subsequently chooses to teach, one is a Sammasambuddha. If one discovers the Dharma without a teacher and chooses not to teach one is a Paccekabuddha.
Also in Theravada Buddhism one is warned against striving for the purpose of attaining some status, and it is further taught that the same Dharma (truth or teaching) both attract, guides and saves living beings. No distinction in truths or teachings is being made (as is sometimes common in Mahayana), although not everyone is taught in the same way (people have different characters and inclinations).