A spelling tutor script for OSX (you need to have a working `say` command)

spell_tutor.rb

#!/usr/bin/env ruby
require 'optparse'

SPELLINGS = Hash.new { |hash, key| key }
SPELLINGS['n'] = 'an'
SPELLINGS['z'] = 'zet'

command = :none
parser = OptionParser.new do |opts|
  opts.banner = "Usage: spell_tutor.rb [--spelling|--dictation]"
  opts.on('--spelling', 'Practice spelling out words') do
    command = :spelling
  end
  opts.on('--dictation', 'Practice letter-by-letter dictation') do
    command = :dictation
  end
end

class Dict
  DICT_PATH = '/usr/share/dict/words'

  def initialize
    @entries = []
    File.foreach(DICT_PATH) do |line|
      @entries << line
    end
  end

  def pick_word
    begin
      pick = @entries.sample
    end until pick.size <= 8
    pick.downcase
  end
end

def practice_spelling
  puts 'Spelling!'
  dict = Dict.new
  loop do
    word = dict.pick_word
    puts "Spell: #{word}"
    press_enter_to 'get a sample spelling'
    spell word
  end
end

def practice_dictation
  puts 'Dictation!'
  dict = Dict.new
  loop do
    word = dict.pick_word
    press_enter_to 'listen to the next word'
    spell word
    press_enter_to 'reveal the word'
    puts word
    puts
  end
end

def spell(word)
  text = word.scan(/\w/).map do |c|
    SPELLINGS[c]
  end.join(' . ')

  %x(say -r 160 #{text})
end

def press_enter_to(action)
  puts "(press enter to #{action})"
  readline
end

parser.parse!
case command
when :spelling
  practice_spelling
when :dictation
  practice_dictation
else
  puts parser
end