Sorry for late reply, actually I forgot about your question.. sorry!
Anyway what were the differences created by English between Tamils and Sinhalese?
After the country taken over by English in 1815 they had to do follow the Sinhalese rituals to keep Sinhalese happy and it was one of the conditions too! But as we all know that did not happen and as a result in 1818 the famous "Wellasse Battle (Uprising)" happened!
After this indecent one of the solutions that English were keen to implement was to somehow destroy the "Udarata Elite Class" and to breed a new class of Tamils whom can speak English, this long term plan was actually later revealed by Leonard Wolf (the author of "Baddegama")
To make this happen the missionaries from the church were sent to Jaffna and this is why at that time Tamils spoke English better than any Sinhalese!
Later.. the legal framework to suit this was bought on by the "Colebrook Reforms"
1. The Thesawalamei Law
This Law helped Tamils to indirectly have all the lands for themselves as Sinhalese were not permitted to buy lands from the North Parts (this law continues till today if I'm not mistaken.. not so sure though)
2. Forced Migration of Tamils from South India
The workers whom English bought into Sri Lanka to do all the labor work, they were settled in Jaffna and Upcountry without sending back! Although later Sri Lankan govt. did send back some of them, upto this day SL Govt. grant citizenship to them every year!
3. In the counsil, Sinhalese and Tamils were given 1 representative each!
Sinhalese comprised of 85% of the population where as Tamils were 8% but Sinhalese were only given 1 representative, the same number as Tamils
4. Until 1920's Manning Reforms, the majority of govt. servants were Tamils
Doctors, Accountants, Engineers, Railway Station Masters, Post Masters, University Lecturers, Clerks..... all these positions were monopolized by Tamils, all this as a result of free education by the English only for Tamils.
As a result of all these backing from English, Tamils actually lived better lives and they were more educated than Sinhalese under English! But now you can understand that when English left the Island in 1950's the situation was beginning to change, people like Anagarika Dharmapala, Henry Olcott fought for Sinhalese Education Buddhist schools were coming up with govt. backing!
Those Tamil Elite class did not like this... the rising of Sinhalese wasn't good for their pocket, everything they enjoyed, and expected under English rule now seemed a far cry all of a sudden,
THIS WAS THE BEGINNING OF ALL PROBLEMS!!