Method of Salaah

Q: If I move my lips and tongue in my own individual namaaz but not to such an extent that I can hear myself had there to be pin-drop silence, is my salaah valid?

Q: I have read that during namaz one should focus on the words being recited. But if one does not know the meaning of those words, how is it possible to "focus" on those words? Should we imagine that we are actually "seeing" those words written somewhere, similar to focusing on text written in a book.

Q: Should the feet be kept together or apart in sajdah? All this while I used to have it together until I read in the Majlis that there is no basis for it. What should I do?

Q: Can one read something in salaah if the imaam is taking too long for example I finish read at-thiyatu or durood ebrahim then in the remainin time left, also please tell in which other parts of salaah this can be done?

Q: Please mention the different views about manner of pointing finger in tashahhud that are stated on this PDF booklet in volume 1, pages 120-135:

http://www.archive.org/details/rabdin_pdf_ara

Also when should one flatten hand on thigh, before first taslim or after both taslim?

Q: Must a Hanafi fold his hands after ruku when he prays behind a imaam who does longer zikr than ''Rabbana lakal hamd'' such as;

رَبَّنا وَلَكَ الحَمْدُ حَمْداً كَثيراً طَيِّباً مُبارَكاً فيه

Rabbana wa laka l-h'amd, h'amdan kathiran tayyiban mubaarakan fih

Q: I read in a book that if you change a letter during recitation in salaah, the salaah is broken. Such as reading the letter ت instead of  د such as at the end of Surah al Falaq reading HASET instead of HASED. But somehow when I recite HASED no matter how much I pay attention to recite it with D I hear a T sound at the end coming out. Does this still break salaah? To break salaah does it need to change meaning, if HASED is read as HASET does it change meaning?

Q: In sajdah if the two hands are placed on the ground but only a part of the palm and the tips of the fingers are touching the ground does this affect the salaat?

Q: If I read maghrib, esha and fajr alone at home, do I have to read it loudly or its just preferable?

Q: Is it ok if I make English dua or Portuguese dua in sajdah in farz or nafl namaaz? One Aalim from Portugal said I can. After all, he is a learned Aalim, whats wrong if I follow him? All mazhabs are correct after all.