A naïve Scala implementation of Peter Norvig's Spelling Corrector from http://norvig.com/spell-correct.html Optimized for neither readability nor brevity nor performance.

SpellCheck.scala

object SpellCheck {
  val alpha = "abcdefghijklmnopqrstuvwxyz"

  val model = scala.io.Source.fromFile("big.txt")
    .getLines()
    .flatMap(_.toLowerCase.split("\\W+"))
    .foldLeft(Map.empty[String, Int].withDefaultValue(1)) { (acc, word) =>
      acc + (word -> (acc.getOrElse(word, 0) + 1))
    }

  def known(words: Set[String]) = words.intersect(model.keySet)

  def edits1(word: String) = {
    val lcWord = word.toLowerCase
    val splits = lcWord.inits.map(i => (i, lcWord.drop(i.length))).toSet

    splits.collect {      // deletes
      case (a, b) if b.length > 0 => a + b.drop(1)
    } ++ splits.collect { // transposes
      case (a, b) if b.length > 1 => a + b.take(2).reverse + b.drop(2)
    } ++ splits.flatMap { // inserts
      case (a, b) => alpha.map(a + _ + b)
    } ++ splits.collect { // replaces
      case (a, b) if b.length > 0 => alpha.map(a + _ + b.drop(1))
    }.flatten
  }

  def known_edits2(word: String) = known(edits1(word).flatMap(edits1))

  def apply(word: String) = {
    known(Set(word)).headOption
      .orElse(known(edits1(word)).toSeq.sortBy(model).lastOption)
      .orElse(known_edits2(word).toSeq.sortBy(model).lastOption)
      .getOrElse(word)
  }
}