ASC. Is it allowed to talk in salah inorder to correct the imam because I have seen a man correcting the imam by speaking to him in English while praying.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Speaking in prayer to correct the Imaam is permissible if he makes a mistake in his recitation. It is obligatory to correct his mistake if it occurs during the recitation of Al-Faatihah. According to Mataalib Ouli An-Nuha Explaining Ghaayat Al-Muntaha, which is a Hanbali book: “It is obligatory to correct the mistakes of the Imaam if he stops or makes a mistake when reciting Al-Faatihah.”

According to Al-Mudawwanah of Imaam Maalik, “If the Imaam stops while reciting, one behind him should correct him.”

According to Kanz Ad-Daqaa‘iq, a book of Hanafi Fiqh, “In conclusion, the strongest opinion is that correcting the Imaam does not invalidate the prayer of anyone - neither the one who corrects nor the one who is corrected, in any way.”

For more benefit, kindly refer to the Fataawa 4195 and 100165.

Also, according to some scholars, speaking in prayer is allowed for the interest of the prayer, such as if the Imaam forgets to fall prostrate or bow and does not understand what those behind him mean when they say "Subhaanallaah". Imaam An-Nawawi divided speaking in prayer into three situation types, saying: "First, speaking deliberately not for the interest of the prayer: His prayer is invalid according to the consensus of the scholars. Ibn Al-Munthir and others reported the consensus of the scholars regarding that.

"Second, speaking for the interest of the prayer, such as if the Imaam stands for a fifth Rak‘ah and someone says, ‘you have prayed four Rak‘ahs’ or something similar: In this case, we, as well as the majority of scholars, hold that the prayer is invalid. Al-Awzaa‘i said that it is not invalid. Maalik and Ahmad are also cited as saying so in one of their opinions.”

The correct opinion is that speaking for the interest of prayer does not invalidate it, as the Hadeeth of Thul-Yadayn provides: “The Prophet, sallallaahu ‘alayhi wa sallam, said the Tasleem after two Rak‘ahs in a four-Rak'ah prayer. Then Thul-Yadayn stood up and said: ‘O Messenger of Allaah! Has the prayer been shortened or have you forgotten?’ The Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said: ‘Is Thul-Yadayn right?’ They said: ‘Yes, he is.’ So the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, stood up and prayed two more Rak‘ahs and said the Tasleem, then he said Takbeer and made the two prostrations of forgetfulness.” [Al-Bukhari and Muslim]

This indicates that the prayer was not invalidated by the question of Thul-Yadayn.

An-Nawawi said that the third type is: “speaking forgetfully, but not for a long time. We view that his prayer is not invalidated and that is the opinion of the majority of scholars.”

On the other hand, if someone speaks deliberately while not knowing the ruling of speaking in prayer, many scholars view that his payer is not invalidated. Shaykh Al-Islam Ibn Taymiyyah said: “The prayer of the one who speaks forgetfully or unknowingly is not invalidated. Ahmad is also cited as saying so.”

Allaah Knows best.