Prakrit partially coincident with Apabhraṃśa
According to the Prākrṭa Prakāśa, an ancient Prakrit grammar, "Prākṛtam is the prakṛti (source) - and the language that Sanskrit originates, or comes from, that prakṛti, is therefore called prākṛtam."
Hemacandra (a Jain grammarian of the 10th century who lived in Gujarat) in his grammar of Sanskrit and Prākrit named Siddha-Hema-Śabdanuśāsana, defines prākṛt's origin to be sanskṛt: "prakṛtiḥ saṃskṛtam, tatrabhavaṃ tata āgataṃ vā prākṛtaṃ"[Sanskrit is the prakṛti (source) - and Prākṛta is so called because it either 'originates-in' or 'comes-from' Sanskrit.]
Another prākṛt grammarian, Mārkaṇḍeya, writes in his grammar Prākṛtasarvasva - "prakṛtiḥ saṃskṛtaṃ, tatrabhavaṃ prākṛtam ucyate“ [Sanskrit is called the prakṛti (origin), and from there prākṛtam originates].
Dhanika, in his 'Daśarūpakāvaloka' commentary on Daśarūpaka (one of the most important treatises explaining the 10 types of Indian Drama), says: "prakṛter āgataṃ prākṛtam, prakṛtiḥ saṃskṛtam" [from the prakṛti (source) comes prākṛtam, and that prakṛti is Sanskrit]
Siṃhadevagaṇin while commenting on Vāgbhaṭālaṅkāra writes: "prakṛteḥ saṃskrtād āgataṃ prākṛtam" [from Sanskrit (which is the source i.e. Prakṛti) - comes Prākṛt]
The Prākṛtacandrikā (a grammar of Prākṛt) says: "prakṛtiḥ saṃskṛtaṃ, tatrabhavatvāt prākṛtaṃ smṛtam" [Sanskrit is the prakṛti, it is remembered that prākṛtam originates from that (prakṛti)]
The Prākṛtaśabdapradīpikā of Narasiṃha says: "prakṛteḥ saṃskṛtāyāstu vikṛtiḥ prākṛtī matā" [Alterations/changes (vikṛti) of the original Sanskrit - is known as Prākṛt]
The Ṣaḍbhāṣācandrikā of Lakṣmīdhara says the same thing as the above: "prakṛteḥ saṃskṛtāyāstu vikṛtiḥ prākṛtī matā" [Alterations/changes (vikṛti) of the original Sanskrit - is known as Prākṛt]
Vāsudeva, in his Prākṛtasaṃjīvanī commentary on Rājaśekhara's Karpūramañjarī says: "prākṛtasya tu sarvameva saṃskṛtaṃ yoniḥ" [Sanskrit is the mother of all Prākṛt]
Nārāyaṇa, in his Rasika-sarvasva commentary on the Gītāgovindam of Jayadeva, says: "saṃskṛtāt prākṛtam iṣṭaṃ tato 'pabhraṃśabhāṣaṇam" [From Sanskrit is derived proper prākṛt, and from that is derived the corrupt-speech i.e. apabhraṃśa]
Śaṅkara, in his Rasacandrikā commentary on the Abhijñānaśākuntala (play by Kālidāsa) says something slightly different from the above: "saṃskṛtāt prākṛtam śreṣṭhaṃ tato 'pabhraṃśabhāṣaṇam" [From Sanskrit is derived best prākṛt, and from that is derived the corrupt-speech i.e. apabhraṃśa]
partially overlapping with partially intersecting with partially sharing with partially matching with partially aligning with