I do have this tendency of treating the southern Indian states are Tamil/Dravidian areas.
How Kerala diverged from Tamil Nadu - Sri Lanka
Kerala & Tamil Nadu were part of one area known as Tamilakam, and therefore shared the same language, culture and ethnicity.
Malayalam, Kerala`s main native language, believed to be originated as an offshoot of Tamil, the principal native language of neighboring Tamil Nadu]. However the language also has some peculiar similarities with Costal language of Karanataka. Malayalam (Derived from the local words: mala(means Forest) and aalam (means Kingdom)) as a composite phrase means the living/inhabitants of Forest Kingdom. This phrase, which in earlier times implied the geographical location of the region, was later replaced by Kerala.Kerala and Tamil Nadu diverged into linguistically separate regions by the early 14th century. The ancient Chera empire, whose court language was Tamil, ruled Kerala from their capital at Vanchi Karuvur (modern Karur in Tamil Nadu). Kerala at that time was composed of two Koduntamizh (deviant Tamil) regions, Venadu (later called Travancore) and Kuttanadu (Malabar). Allied with the Pallavas, they continually warred against the neighbouring Chola and Pandya kingdoms. Until the Bhakti age, the Sangam Tamil Cheras of the Kongu Nadu region in Tamil Nadu controlled both these regions. History says that (recorded im Mackenzie records) a Chozha princess was married to the Chera of Karur and he got a dowry of 48,000 agriculturists from the Chozha country. These people were settled in the then forested region of Venadu and Kuttanadu and thus the first agricultural settlements arose in what is called Kerala today.
A Keralite identity, distinct from the Tamils and associated with the Kerala Varmans empire and the development of Malayalam, subsequently evolved sometime during the 8th 14th centuries. Meanwhile, both Buddhism and Jainism reached Kerala in this early period. As in other parts of ancient India, Buddhism and Jainism co-existed with early Shaivite beliefs during the first five centuries. It was only after the Sangam period that Kerala saw large-scale immigration of Brahmins from the north. These influxes may have coincided during the Kalabhras, Rashtrakuta, Chalukya, Pallava and Hoysala invasions. By the 8th and 9th centuries, 2nd Chera kings inclined to Vaishnavism and some of them wrote great literary works in the stream of Vishnu Bhakthi. When Hinduism was revived by intellectuals like Shankara and by Bhakti movements all over India, Buddhism and Jainism merged into their mother religion.
EVOUTION OF THE MALAYALAM LANGUAGE AND LITERATURE
With Tamil, Kota, Kodagu and Kannada, Malayalam belongs to the southern group of Dravidian languages. Its affinity to Tamil is the most striking. Proto-Tamil Malayalam, the common stock of Tamil and Malayalam apparently disintegrated over a period of four of five centuries from the ninth century on, resulting in the emergence of Malayalam as a language distinct from Tamil. As the language of scholarship and administration Tamil greatly influenced the early development of Malayalam. Later the irresistable inroads the Brahmins made into the cultural life of Kerala accelerated the assimilation of many Indo-Aryan features into Malayalam at different levels.
The earliest written record of Malayalam is the /vazhappaLLi/ inscription (ca. 830 AD). The early literature of Malayalam comprised three types of composition. The earliest extant prose work in the language is a commentary in simple Malayalam, Bhashakautaliyam (12th century) on Chanakya`s Arthasastra. Malayalam prose of different periods exibit degree of influence of different languages such as Tamil, Sanskrit, Prakrits, Pali, Hindi, Urdu, Arabi, Persian, Syriac, Portuguese, Dutch, French and English. Modern literature is rich in poetry, fiction, drama, biography, and literary criticism
In the early thirteenth century /vattezhuthu/ (round writing) traceable to the pan-Indian brahmi script, gave rise to the Malayalam writing system, which is syllabic in the sense that the sequence of graphic elements means that syllables have to be read as units, though in this system the elements representing individual vowels and consonants are for the most part readily identifiable. In the 1960s Malayalam dispensed with many special letters representing less frequent conjunct consonants and combinations of the vowel /u/ with different consonants.
Malayalam now consists of 53 letters including 20 long and short vowels and the rest consonants. The earlier style of writing is now substituted with a new style from 1981. This new script reduces the different letters for typeset from 900 to less than 90. This was mainly done to include Malayalam in the keyboards of typewriters and computers.