‘Ameen‘ means effectively ‘O Allah! Respond (to the du’a)!’. The purpose of saying ‘Ameen‘ is to increase the chances that a person’s du’a might be answered. It is like repeating the du’a over again, except instead of going into all the details, it is all summarised in the phrase ‘Ameen‘.
When a person is listening to another person make du’a, it is recommended to say ‘Ameen‘. There are particular dua’s that are more suitable for a group context, such as that done in qunut, where the imam makes a du’a and the congregation behind him says ‘Ameen‘. Similarly, when the imam makes du’a during the Jummuah khutbah, it is recommended to say ‘Ameen‘ after his du’a. It is also encouraged to say ‘Ameen‘ after reciting Surah al-Fatihah, regardless of whether one is praying or reciting it outside of prayer, or whether one is the imam or the follower. At all such times ‘Ameen‘ should be recited with an audible voice. It is an innovation however, to have a group du’a after finishing salah.
Some du’as should be done privately such as those one recited during the day or night, and it is also permissible to say ‘Ameen‘ after these. When Musa, peace be upon him, prayed to Allah to punish Pharaoh, it is said that Harun was behind him saying, ‘Ameen‘. Even though only Musa was actually saying the du’a, Allah says in the Qur’an:
“Your (both of you) prayers have been answered!” (Surah Yunus:89)
This is proof that the one who says ‘Ameen‘ to a du’a is like the one who made du’a.
One last point to note is that many people do not pronounce the phrase ‘Ameen‘ correctly. Some common mistakes include:
- Prolonging the alif so that it becomes ‘Aaaaaameen’. The first alif should not exceed two harakahs in length.
- Making the alif too short, it should be two harakahs, not less.
- Placing an assimilation on the meem, so that it becomes ‘Ammmeen’. The meem has a kasrah on it but no shaddah.
As for the last syllable, it is permissible to shorten it to two harakahs or prolong it to six. So to say ‘Ameeeeen’ is allowed. And Allah knows best.