‘Ameen’ is recitation in prayer after Surah Al Fatiha. Pronounced loudly in Arab tradition but silently in India and Pakistan. Although not part of the Book but it is deep in human reflection. Saying Ameen is affirmation of intention as outlined in the opening chapter. Though voicing Ameen is inherently habitual among so many ritual Muslims, it must be cognitively thought-out to verily and truly agree with the verses.
And though it is derived from Christian and Judaic tradition, but what ground to say in the light of above that Ameen is cultural than the affirmation of sacredness!