'own speciality' is correct and usable in written English.
You can use 'own speciality' to refer to someone's particular field of expertise. For example: "John is an expert in HTML, which is his own speciality".
I think it's best for everyone to stick to their own speciality".
❦ Learning to withstand emptiness was her own speciality, her given task.
Ekiben are popular bento-style lunchboxes sold at railway stations throughout the country and each area has its own speciality.
LegoSuperstar was even able to identify her own speciality: "I'm a poisons expert, if the look on the children's faces at teatime is anything to go by".
That day, we roamed the narrow, dusty streets and the maze of bazaars, each one with its own speciality: silks, spices, homeware, electrical goods, tailoring.
My own speciality, slang dictionaries, may engender a good deal of browsing, but slang fans also want to discover what an entry means.
Towns have their own specialities, such as peppery olive oils or egg-yolk based desserts.
Every region has its own specialities, reflecting a unique part of Sweden's geography and its distinct four seasons.
Generally, a large menu is something to be suspicious of, but with so many cooks, each responsible for their own specialities, there is no chance of spoiled broth.
Throw in influences from nearby Thailand and Indonesia and it's easy to see why there's a huge variety of cuisines across the country, with many states boasting their own specialities and classic dishes.
Well, every German Christmas market has its own specialities (the best wooden ornaments come from the Erzgebirge mountains; the Bavarian Forest produces superb glass) but if you're planning a special trip to Germany to do your Christmas shopping, it makes sense to visit a market in a place you want to see in its own right.
