Since this is old, you may have to see how much of it still works.
Note that I used Minion Pro for English and Lohit Devanagari for Hindi. You may have to check what fonts are installed on your system, and modify these accordingly.
And I have this in my emacs config, which allows me to use arabic numbers with devanagari script (since I don't want to use devanagari numbers even when I am writing devanagari):
;; Function to mix Devanagari with Arabic numbers
(require 'ind-util)
;; based on:
;;
https://github.com/emacs-mirror/emacs/blob/30c09955f64815201ae9b86215fed8ea2af0ba66/lisp/language/ind-util.el#L464(defun indian-make-hash-without-digits (table trans-table)
"Indian Transliteration Hash for decode/encode"
(let* ((encode-hash (make-hash-table :test 'equal))
(decode-hash (make-hash-table :test 'equal))
(hashtbls (cons encode-hash decode-hash))
(vowels (elt table 0))
(consonants (elt table 1))
(misc (elt table 2))
(digits (elt table 3))
(halant (char-to-string (elt misc 4)))
(trans-vowels (elt trans-table 0))
(trans-consonants (elt trans-table 1))
(trans-misc (elt trans-table 2))
(trans-digits '("0" "1" "2" "3" "4" "5" "6" "7" "8" "9")))
(indian--puthash-v vowels trans-vowels hashtbls)
(indian--puthash-c consonants trans-consonants halant hashtbls)
(indian--puthash-cv consonants trans-consonants
vowels trans-vowels hashtbls)
(indian--puthash-m misc trans-misc hashtbls)
;; (indian--puthash-m digits trans-digits hashtbls)
hashtbls))
;; based on:
;;
https://github.com/emacs-mirror/emacs/blob/30c09955f64815201ae9b86215fed8ea2af0ba66/lisp/language/ind-util.el#L486(setq indian-dev-itrans-v5-hash-without-digits
(indian-make-hash-without-digits indian-dev-base-table
indian-itrans-v5-table))
;; needed for the quail-define-indian-trans-package function:
;;(add-to-list 'load-path "~/emacs/lisp/leim/")
(load "leim/quail/indian.elc")
;; (load "quail/indian.el.gz")
;; based on:
;;
https://github.com/emacs-mirror/emacs/blob/30c09955f64815201ae9b86215fed8ea2af0ba66/lisp/leim/quail/indian.el#L56(quail-define-indian-trans-package
indian-dev-itrans-v5-hash-without-digits "devanagari-itrans-without-digits" "Devanagari" "DevIT"
"Devanagari transliteration by ITRANS method, with Arabic numerals.")