The classification of Indian languages into Dravidian and Indo-European is well known. I would like to propose a new classification based on pronunciation -- South and North Indian.
1. Pronunciation of the vowels 'ai' and 'au'
If the vowels rhyme with "why" and "cow" respectively, the language is South Indian. If they are pronounced like "way" and "cause" respectively, the language is North Indian.
2. Pronunciation of the conjunct consonant 'jJa'
If it is pronounced as 'gya', the language is North Indian.
3. Pronunciation of the aspirate 'pha'
If the consonant is pronounced as F, the language is North Indian.
4. Extent of eliding the vowel 'a'
This criterion is more of degree than black-and-white. The extent of elision is close to 100% in North Indian languages.
In the case of Marathi, it meets all the criteria except the third. Observe how a Marathi speaker pronounces the words vaidya, gaurava, jJAna. Also note the non-elision of the vowel 'a' in the names Ranade, Thackeray and Fadake, and in the Varakari chant 'viTThala, viTThala.'
By the same token, Sanskrit is a South Indian language too.