So if simply asking hasn’t worked, it’s time to make listening to you more interesting! This is especially important when your level is much lower. So, tell them passionately why you would like to practise (once again in their language). This can appeal to their human nature and make it much more personal and have them more interested in helping you. After occasionally getting answered in English here in Prague, I tell them about my 3-month mission. Mine is such a ridiculous story (fluent in Czech in 3 months?!?) that at worst, it holds their attention a little longer. At best it convinces them that maybe I am worth helping. Tell them that you are trying to discover your roots, or how you’ve always dreamed of one day speaking their language, etc.