My dear friend,
Free lesson: Change the title of the topic You can write "Let's start speaking English"
You cannot use 2 bare verbs together in English. A verb must be followed by a gerund (speaking) or an infinitive (to speak). This rule depends on the verb; some verbs take gerund, some verbs to infinitive and some takes both of them (like start)

Using this information will make you sound less amateur.
Good luck, cheers!

Hello Ömer why do you think you must forget your native language? Contrary to what you said you should know your native language well for learn an another language. Do you want to learn language? Solution is speak, go outside meet new people and speak with them they will help you and you will see how much improve yourself. I wish you best luck