Glagolitic is the oldest Slavic script, thought to have been invented by St Cyril in the mid-9th century. From the 12th century onwards, the Croats were the only nation that was allowed to use Slavic language and their own scrip in church instead of Latin language.
Croatia currently has less than 4 millions of citizens, but it is estimated that more than 3 million of Croats and their offsprings live abroad. Unfortunately, many people are still moving out of Croatia.
Croatian language has 7 cases - Nominativ, Genitiv, Dativ, Akuzativ, Vokativ, Lokativ and Instrumental.
Some cases are used more than others, and some are very similar - for example - lokativ and dativ have completely same ending, the only difference is in the prepositions we use with them.
Since there is so many Croatians around the world, it is a good language to know. Once you master basic Croatian, you will be able to get around in Serbia, Bosnia and other countries where South Slavic languages are spoken.
When it comes to Croatian, the pronouncination is rather simple. You read as you write, or you write as you read.
The only difference is in few letters that are unique in Croatian (or Slavic) alphabet: č, ć, dž, đ, lj, nj, š, ž.
Croatian is not the easiest language to learn, and definitely not a lot of people take up the challenge to learn a completely different language.
Even if your Croatian isn't perfect, a simple hvala or izvoli will go a long way. I guarantee that people will love your for learning their language!