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[dubious ], in Mahayana texts like Shantideva's Bodhisattvacharlavadacrechlkyadifaeikyavatara and in the Tibetan tradition, and refers to an enlightened disciple of the Buddha.
Samyaksambuddhas (Pali: Sammasambuddha) gain Nirvana by their own efforts, and discover the Dhamma without having a teacher to point it out. They then lead others to enlightenment by teaching the Dhamma in a time or world where it has been forgotten or has not been taught before, because a Samyaksambuddha does not depend upon a tradition that stretches back to a previous Samyaksambuddha, but instead discovers the path anew. The historical Buddha, Gautama Buddha, is considered a Samyaksambuddha. See also the list of 28 sammasambuddhas.
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.
Pratyekabuddhas (Pali: Pacceka Buddha) are similar to Samyaksambuddhas in that they attain Nirvāṇa without having a teacher. Unlike the Samyaksambuddha however, they do not teach the Dhamma that they have discovered. Thus, they also do not form a Saṅgha of disciples to carry on the teaching, since they do not teach in the first place.
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).
Śrāvaka (Skt.; Pali: sāvaka; means "hearer" or "follower") is a disciple of a Sammasambuddha. An enlightened disciple is generally called an arahant (Noble One) or ariya-sāvaka (Noble Disciple). (These terms have slightly varied meanings but can both be used to describe the enlightened disciple.) The Theravadin commentary to the Udana uses the term sāvaka-buddha (Pali; Skt. śrāvakabuddha) to describe the enlightened disciple This third types of Buddha is also acknowledged in Mahayana texts  and in Tibetan Buddhism.
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.
Teaching and Studying
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).
- Bodhisattvacharyavatara by Shantideva, translation Alexander Berzin, Chapter 10 verse 50
- Nonconceptual Cognition of Voidness by Shravaka, Pratyekabuddha, and Bodhisattva Aryas According to the Four Tibetan Traditions, by Alexander Berzin
- Udana Commentary, tr Peter Masefield, volume I, 1994, Pali Text Society, page 94).
- Bodhisattvacharyavatara by Shantideva, translation Alexander Berzin
- Ratanasutta:56. Also see AN 4.1, entitled "Anubuddha Sutta" (Thanissaro, 1997).
- Simile and Parable, chapter 3 of the Lotus Sutra, translated by Burton Watson, 1994, Columbia University Press, online edition courtesy Soka Gakkai International
- The Bodhisattva Ideal in Theravada, Jeffrey Samuels, Philosophy East and West, v47, n3, July 1997, pp399-415
- Pacceka Buddha in Dictionary of Pali Proper Names
- The Paccekabuddha: A Buddhist Ascetic. Ria Kloppenborg. Brill, Leiden, Netherlands: 1974.
- "Bodhisattva Ideal in Buddhism" by Ven. Dr. W. Rahula, from Gems of Buddhist Wisdom, Buddhist Missionary Society, Kuala Lumpur, Malaysia, 1996. (Retrieved 2007-05-27.)