As already stated length of stay is always determined at the border which is why I asked about personal funds to cover her costs for a longer period of time. Many people are unaware that being granted a TRV doesn’t guarantee a 6 month stay. It is always determined at the border and is based on the ability to support yourself for up to 6 months, whether there are any concerns that you may work while in Canada, whether you have any medical needs that could place demands on the healthcare system and whether you have travel medical insurance (for example if you arrive in the 3rd trimester of pregnancy there may be concerns about your potential desire to give birth in Canada and whether you’ll be able to fund the healthcare needed if you do end up giving birth in Canada), whether you have strong ties to your home country to alleviate any concerns that you will leave when your permit expires (family, employment, property especially a home,etc.). Learning the language is also not something a typical visitor does but a language course for up to 6 months is allowed with a TRV so her goal to improve her language skills is possible just a different reason for her to come to Canada versus visiting her sister and her children.