Insert random Japanese Hiragana to overlearn them

Here are some functions I wrote to create a page of random hiragana for me to exercise for character recognition. The main goal is to learn to recognize quickly hiraganas and pronunce them correctly. As hiragana are written in a random order, it's not an exercise for learning to read japanese :

(defun delnth (n l)
 (if (zerop n)
     (cdr l)
   (let ((prev (nthcdr (1- n) l)))
     (setcdr prev (cddr prev)))
   l))

(defun random-insert (nb l)
 (let ( (remaining (copy-sequence l) ) (inserted nil) (num -1) )
   (while (> nb 0)
     (while (and (> (length remaining) 0) (> nb 0))
       (setq num (random (length remaining)))
       (setq elem (nth num remaining))
       (insert elem)
       (setq inserted (cons elem inserted))
       (setq remaining (delnth num remaining))
       (setq nb (1- nb)))
     (if (> nb 0)
         (progn
           (setq remaining inserted)
           (setq inserted nil))))))

(defvar jp-hiragana '("か" "け" "き" "こ" "く" "じゃ"
                     "ぐ" "げ" "が" "ご" "ぎ" "と"
                     "て" "た" "お" "ひゃ" "あ" "え"
                     "い" "しゅ" "みゅ" "ぷ" "ぴゅ"
                     "ぱ" "ぺ" "ぴ" "う" "ぽ" "びゅ"
                     "じょ" "みょ" "ぴょ" "よ" "や"
                     "ゆ" "ひ" "ほ" "は" "へ" "きょ"
                     "ど" "で" "だ" "ちゃ" "しょ" "ぎゃ"
                     "つ" "りょ" "ぎょ" "め" "ま" "も"
                     "きゅ" "み" "む" "ちょ" "じゅ" "し"
                     "ひょ" "ぞ" "ぜ" "ざ" "ず" "づ"
                     "びょ" "ぎゅ" "ん" "る" "にゃ"
                     "れ" "ら" "ろ" "り" "ひゅ" "りゃ"
                     "に" "の" "な" "ね" "ぬ" "びゃ"
                     "りゅ" "じ" "ぢ" "ち" "わ" "を"
                     "ふ" "にゅ" "す" "そ" "さ" "べ"
                     "せ" "ば" "ぼ" "び" "ぶ" "みゃ"
                     "ぴゃ" "しゃ" "ちゅ" "にょ" "きゃ")
 "List of all Japanese Hiragana with different sonorizations and
 concatenated syllables")

(defun jp-insert-exo (nbchar)
 "Print a page of Japanese exercice."
 (interactive "nNumber of characters to print: ")
 (random-insert nbchar jp-hiragana))

The function delnth returns the list with the nth element removed. Random-insert randomly insert elements of a list of strings or characters. The variable jp-hiragana bring together all hiragana including different sonorization, and syllable concatenation.

The function jp-insert-exo command insert the given number nbchar of hiragana into the current buffer.

One limitation is that hiragana are inserted on a line. One could enhance these functions to correctly write them from top to bottom and left to right.

We can imagine the same kind of thing for katakana or even kanji. This exercise is interesting when you start to learn kana. The goal is to overlearn the kana in order to be really at ease with them.

Print a page or two of them and now, let's practise Hiragana ! Just pronounce each hiragana loudly (or loudly in your head) one after the other.