The App Store is littered with word games, perhaps stemming from the ongoing popularity and intuitive nature of crossword puzzles, word searches and board games such as Scrabble.
For fans of Scrabble - and there are plenty of them, since over 150 million sets have been sold worldwide - EA's iOS versions are a great first port of call.
Scrabble (£1.49, iPhone) and Scrabble for iPad (£4.99, iPad) are both enjoyable and polished, with multiple difficulty levels and several game styles.
Only two things tarnish these otherwise first-rate takes on a classic board-game: the dictionary is annoyingly sanitised (EA seemingly favours 'think of the children' over 'think of the adults, or at least provide them with an alternate dictionary option') and the multiplayer modes don't enable you to play online.
You can set up a local game using Wi-Fi or Bluetooth, or pass-and-play with a single device, but the lack of internet play is astonishing. But where Scrabble flounders, others fill the void, albeit in variable fashion.
Lexulous (£1.49, iPhone) managed to survive a copyright infringement lawsuit when it was Scrabulous, and with the Flash-based original unavailable on iOS, a great native client would have pleased millions of users. Sadly, Lexulous for iOS is dreadful - avoid the £1.49 paid-for version and only grab the free 'lite' release if you've friends that will tear you limb from limb should you not be permanently available to make a move.
A better option is the similarly popular Words With Friends (£1.49, iPhone; £1.99, iPad), which also comes in an ad-supported free version and only really differs from Scrabble in the placement of the board's premium tiles and in its letter values and distribution.
With Scrabble being streamlined and focussed, some developers have used it as the foundation to offer their own spin on the game: AbbleDabble (69p, iPhone; £1.99, iPad) has the premium tiles move around the board, while Wordfeud (free, iPhone) optionally randomises their locations; and War of Words (free, Universal) enables you to blow up your opponent's tiles or pilfer some of their words.
HexaLex (£1.49, iPhone) and WordSnake (69p, iPhone) take things in slightly more radical directions. HexaLex uses hexagonal tiles, which dramatically changes how you approach tile placement. Options enable you to set the maximum number of 'junk' two-letter words (down to zero for purists), and a one-player mode - something surprisingly uncommon in Scrabble-type games - adds value.
WordSnake returns the genre to square tiles, but the board is endless and full of hazards. Your aim is to use a limited number of tiles to link one area of the board with another, to help Elmer the snake reach his sweetheart (who presumably has a word fetish).
Of course, Scrabble also influenced traditional board games, two of which offer iOS equivalents. Upwords - Scrabble with letter-stacking - doesn't exist on iOS, but SkyWords (free, iPhone) is essentially the same game. Sadly, the one-player mode is solitaire (there's no computer opponent), but online games and pass-and-play are supported.
Moxie 2 (£1.49, iPhone; £1.99, iPad) is better for solo players, taking the Upwords system and simplifying it, forcing you to play words within three six-letter slots.
Boggle (£1.49, iPhone) is also popular with Scrabble fans, although it's closer in nature to anagrams than crosswords. Still, with it forcing you to rapidly create words from a grid of letters, it's useful training for the ardent Scrabble player, and the iPhone version is good, if slightly iffy from a control and dictionary standpoint.
Unlike Scrabble, many of Boggle's clones improve on the original; wurdle (£1.49, iPhone) is a fast-paced variant with plenty of grid options; Bookworm (£1.99, iPhone) is a hugely popular take by PopCap that removes letters once words are completed, enabling more to fall into the well, Bejeweled-style; WordPop! (69p, iPhone) works much like Bookworm, but doesn't replace tiles, forcing you to think several moves ahead; Textropolis (free, iPhone) is more sedate and also doesn't require you to draw a path through letters - you instead simply tap them to create words; and Abca (£1.49, iPhone) takes the well-oriented gameplay in the likes of Bookworm and adds features such as virus tiles that infect other letters, bomb letters and locked tiles.
Aside from graphical oddities, Abca is our favourite of these titles, due to the variety of gameplay styles it offers. However, unlike the variable Scrabble clones, every one of the Boggle derivatives mentioned here is pretty good.
We also found some other great word games on the App Store. WordZinga! (£1.49, Universal) presents you with words that have a number of missing letters, and you simply have to fill in the gaps. The game looks rough, but it helpfully tells you how many possibilities are available during each round and it gets you thinking about alternatives.
Word Solitaire: Aurora (69p, iPhone) is a solitaire game with letters - you clear rounds by flipping all of the cards and rearranging them to make a word in each stack.
Our favourite of these titles, though, is Jumbline 2 (£1.49, iPhone; £1.99, iPad), which boasts three games in one. The classic mode simply tasks you with finding as many words as possible from a jumble of five, six or seven letters, only enabling you to continue to the next level once you've unmasked one or more words that uses the maximum number of letters.
When you're playing with seven letters, Jumbline 2 becomes a fantastic tool for Scrabble training (and is actually a better title for solo players), even if the dictionary is occasionally suspect. Two extra modes add further value: Cloud Pop, where you make complete words from letters on floating clouds, and Star Tower, where you build a tower from a jumble of letters. The last of those modes forces quick thinking - bigger words are rewarded with larger blocks, but if the top of the tower falls under the yellow line, it's game over.
And finally, when everything's got a bit too much and you've lost yet another game because your opponent has won, largely by arguing that 'za' is in fact a word in common usage, try Vetica (£1.49, iPhone). Instead of making words from letters, you use your A-shaped ship to obliterate them. Ahhh, catharsis (14 points)!