I want to learn mandarin but like only for 6 months to a year and for only once a week since I am working.

there are a lot of language skills in the philippines.

it depends where you are from.

if your from cebu, visit this website..

speedtalkcenter.com

I know there is Mandarin class in UP every Saturdays but I forgot to where you can contact them. Maybe try calling UP registrar's office. Also try inquiring at the DFA office, they know some language classes/schools. TESDA in Taguig also offer Mandarin classes for a low price, try to call them if they offer extensive/long term classes. TESDA contact number is 887-7777