彼が英語を話しているのを聞くと、英国人とまちがえるでしょう。の英語

Hearing him speak English, one would take him for an Englishman.

To hear him speak English, you would mistake him for an Englishman.

To hear him speak English, you would take him for an Englishman.

To hear him speak English, you'd think he was [you would take him for] British.

To hear him speak English, one would take him for an Englishman.

To hear him speak English, you would take him for a native.

To hear him speak English, you would take him for a native.

To hear him speak English, you would take him for an American.

Born in England, he speaks British English.

To hear him speak English, you would take him for a native speaker.

I often listened to him speak in English.

To hear him speak, you'd take him for a foreigner.

He has studied English under an Englishman.

To hear her speak English, you would take her for an Englishwoman.

He speaks English as well as though he were an Englishman.

To hear him speak English, you would think he was [were] an Englishman.

I think that he can probably speak English.

To hear him talk, you would take him for a foreigner.

He speaks English with a very proper British accent.

He speaks English like a native.

Although he was born in England, he speaks English very badly.

He has only just begun his English, and can not be expected to speak it.

If you heard her speak English, you would take her for an American.

Everyone knows that he speaks English well.

He is a Japanese person who can speak English well.

Can he speak English?

He makes glaring mistakes in speaking English.

He speaks English as if he were an American.

Does he speak English?

Can he speak English?