English is pronounced in many different ways. I am a native speaker from the US Midwest, but I have sometimes found myself utterly baffled by the spoken English of northern England. When you consider the dialectical differences among different regions of the English speaking world and the differences in diction among different individuals speaking the same dialect of English, you should not be surprised to hear great variations in how English is pronounced.
Often in English speech, there is a very slight pause between different words. In that case, you should hear "How will an." But some people may string words together without that pause and then you will hear "how willan."
Hundreds of millions are native speakers of English. Hundreds of millions of people are going to differ.