For learning Tamil language it is necessary to know alphabets in Tamil. You have to know alphabets in Tamil to learn writing in Tamil language. Tamil alphabets are the building blocks of Tamil language. There are 247 characters in Tamil alphabets. Tamil alphabets are made up of Tamil vowels and Tamil consonants. The Tamil alphabets contain 12 vowels and 18 consonants. Tamil vs German gives a comparison between Tamil and German alphabets.
Tamil script is also known as Tamil writing system or Tamil orthography. The set of visible signs used to represent units of Tamil language in a systematic way is called Tamil Script. The Tamil language uses Tamil i.e. Tamil alphabets are derived from Tamil script. The script decides the writing direction of the any language, hence the writing direction of Tamil is Left-To-Right, Horizontal. Learn Tamil Greetings where you will find some interesting phrases.
Is Tamil hard to learn? The answer to this question is that it depends on one's native language. One should start learning Tamil language with Tamil alphabets and Tamil phonology.
Time taken to learn any language that is mentioned here is the approximate time required to learn specific language for the person who is proficient in English. You can also go through all Indian Languages and find if Tamil is one of the language of India.