The Mahanarayana Upanishad (Swami Vimalananda translator) says:
13.4 Narayana is the Supreme Reality designated as Brahman. Narayana is the highest (Self). Narayana is the supreme Light (described in the Upanishads). Narayana is the infinite Self. [Narayana is the most excellent meditator and meditation.]
13.6 One should meditate upon the Supreme--the limitless, unchanging, all-knowing, cause of the happiness of the world, dwelling in the sea of one's own heart, as the goal of all striving. The place for His meditation is the ether in the heart--the heart which is comparable to an inverted lotus bud.
The location for praying to Narayana is in the cave of your heart. What is outside is inconsequential. If certain outside environments are more conducive to helping you concentrate upon Him in the cave of your heart, then do so. As Sri Chaitanya says in one of his poems - "No times are set, no rites are needful, for chanting of Thy name."
Any language that you understand will do. Sanskrit slokas can help if they are pronounced correctly...remember if not pronounced correctly, they can lead to opposite effects. The Lord looks at your heart's intentions, not at your pronunciation.
The Lord gives you what you ask for. But why go before a King and ask for glass beads when there are diamonds to be had? Pray to Him and ask only that you may have only pure love for His lotus feet. If that is given, everything else happens without asking...