If you want to speak English really well, you need to practise your connected speech.

A very common phrase in English is 'have to', right?

Have to.

But when a native speaker says this really quickly, it normally sounds like this.

'Haffda.' Haffda.

With an Australian accent, we say 'haffda'.

So like H A FF, da, D A. Haffda.

So for example, if somebody said to me, 'What are you doing today?', I could say, 'I haffda take this Instagram video.'

I haffda take this Instagram video.

Now you try. I haffda take this Instagram video.

Or, maybe I would say, 'I haffda go to the park to exercise.'

I haffda go to the park to exercise.

Now you try. I haffda go to the park to exercise.

So try this with your friends who are native speakers, and they will think that you are a native speaker.