Increase the font size for Hebrew text in Emacs but leave English font size as is

Question

I frequently type both in Hebrew and English. The font I use is Dejavu Sans Mono. This renders Hebrew fonts accurately. However, because Hebrew uses small vowels, I would like to increase the font size of the Hebrew text but keep the English as it is. I have tried various solutions but none have worked for worked for me:

I installed the package unicode-fonts, but this does not seem to have the ability to tweak font sizes.

I followed the instructions in this link How to assign a certain font for each input method/language in Emacs 24? but found no useful solution there.

I use the code below to change input methods:

  (define-key 'iso-transl-ctl-x-8-map "f" [?‎])

  ;; Input method and key binding configuration.
  (setq alternative-input-methods
        '(("hebrew-biblical-sil" . [?\C-\\])
          ("greek-babel" . [?\C-|])))
  (setq default-input-method
        (caar alternative-input-methods))
  (defun toggle-alternative-input-method (method &optional arg interactive)
    (if arg
        (toggle-input-method arg interactive)
      (let ((previous-input-method current-input-method))
        (when current-input-method
          (deactivate-input-method))
        (unless (and previous-input-method
                     (string= previous-input-method method))
          (activate-input-method method)))))
  (defun reload-alternative-input-methods ()
    (dolist (config alternative-input-methods)
      (let ((method (car config)))
        (global-set-key (cdr config)
                        `(lambda (&optional arg interactive)
                           ,(concat "Behaves similar to `toggle-input-method', but uses \""
                                    method "\" instead of `default-input-method'")
                           (interactive "P\np")
                           (toggle-alternative-input-method ,method arg interactive))))));; Input method and key binding configuration.
(reload-alternative-input-methods)

Answer 1

You can do this with set-fontset-font, which allows overriding the builtin selection mechanisms for fonts for specific characters, charsets or scripts. So in your case, something like:

(set-fontset-font "fontset-default" 'hebrew (font-spec :family "Dejavu Sans Mono" :size 20))

See Modifying-Fontsets for more info.