Alvin, Simon, Theodore, and David Seville are all voiced by Ross Bagdasarian, Sr. in "The Chipmunk Song".
Since the '80s, Alvin, Simon, and Dave have been voiced by Ross Bagdasarian, Jr., while Theodore and all three Chipettes are voiced by his wife, Janice Karman.
Later still, when the series switched to DiC for animation, almost all of the additional one-shot characters were voiced by their associate producer Thom Watkins, with Ross occasionally stepping in for other additional male characters, while Janice voiced most additional female characters.
In the Italian dub, Slappy Squirell from Animaniacs is also Alvin.
Keep Circulating the Tapes: There's never been a complete compilation tape/DVD or box set containing all the episodes. There exists only the aforementioned Sing Along tapes (which just have some of the musical segments) and a DVD called "The Very First Alvin Show" (which only contains one of the first episodes, along with the specials A Chipmunk Reunion and Rockin' Through the Decades).
Talking to Himself: Dave, Alvin, Simon, Theodore and Sam Valiant. Though not fully determined, it is rumored that Clyde Crashcup's voice actor Shepard Menken provided Leonardo the assistant's whispering.
The Other Darrin: This special's the first time both Ross Bagdasarian Jr. and Janice Karman took over the vocal roles of Dave Seville and the Chipmunksnote Ross Bagdasarian Jr. voicing Alvin and Simon with Janice Karman voicing Theodore and would be throughout the franchise until the live action/CGI movies with Jason Lee. note Though Ross still provides Alvin's singing voice, Janice does Theodore and the Chipettes' singing voice and Steve Vining for Simon
Real-Life Relative: Husband and wife Ross Bagdasarian Jr. and Janice Karman picked up the franchise. Then later on, their kids Vanessa and Michael started helping them.
Actor Allusion: Grandpa Seville, a farmer, is voiced by Alan Young, who not only voice Farmer Smurf but he has played another farmer before in 1952 movie Aaron Slick from Punkin Crick as titular Aaron Slick.
Beam Me Up, Scotty!: A rare visual example. For many years, fans believed that the infamous "Sploosh" episode had Simon and Jeanette kissing (mostly thanks to the few screencaps from the episode circulating around the internet including a cap of them leaning in for a smooch). When the episode finally surfaced briefly on YouTube in 2011, and officially released on DVD later that same year, it turns out The Big Damn Kiss was nothing more than an Almost Kiss.
Edited for Syndication: 65 episodes were syndicated by Lorimar-Telepictures in 1988. They were the first five seasons, both Valentines and Reunion primetime specials, and the 11 Murakami-Wolf-Swenson episodes from season 6. In most markets, almost every episode from the first three seasons, as well as a handful from the fourth are sped up (similar to PAL) to conserve time for longer commercial breaks. Some season 3 episodes left the speed alone, but trimmed certain scenes out. In the U.S., a later broadcast on the Cartoon Network left out the the individual episode title cards from the Ruby-Spears episodes, though international markets always retained them.
Bagdasarian Productions keep re-releasing the exact same compilation DVDs (with maybe an additional entry or two with certain releases) year after year, under different titles.
Different episodes, in different forms, continually pop up on various different video sharing sites, such as YouTube or Dailymotion, though they do suffer from being pulled for copyright, whether from Bagdasarian Productions, or other companies such as Warner Bros. (particularly uploads from Cartoon Network recordings).
Talking to Himself: Really taken to new levels during the DiC era of the show; by then, Ross Bagdasarian, Jr. and Janice Karman did almost all of the voices themselves (notice an increase in characters who sound almost like Dave, and all the female characters have the same voice), while their associate producer, Thom Watkins, did the rest. By then, the only characters who weren't voiced by Bagdasarian, Karman, or Watkins were Miss Miller (Dody Goodman) and Lilly the puppy (Frank Welker).
Write Who You Know: In "Cookie Chomper III", the dog the Chipmunks adopted is named Lilly. Lilly the puppy was named after Ross Bagdasarian Jr. and Janice Karman's dog, Tiger Lily, who served as the real-life inspiration for this episode. Like Cookie Chomper III, Tiger Lily was also run over by a car and died.
Production of the movie became too time consuming, and with the deadline for the completed project fast approaching, several scenes in the original script had to be re-written to make them simpler for the animators to animate (including the sacrificing scene), or cut from the script completely, thus resulting in a much shorter movie with fewer locations The Chipmunks and Chipettes actually visit.
Early concept art also reveals that the producers originally intended to have a scene where the boys drop off a doll in a church confessional and that the sacrifice scene was originally set on top of a Mayan pyramid instead of a crocodile pit. Another sketch shows the boys in some sort of sewer or prison with two men prying open bars at an opening at the top.
Executive Meddling: Ross Bagdasarian, Jr. and Janice Karman were set to voice the characters for the first film, (they had already done some of the voices in the trailers), and Ross was even going to play Dave, however, Twentieth Century Fox rejected this, and insisted that younger people do the voices and a younger actor for the role of Dave... though, there is speculation that Fox made this move because they wanted more marketable names attached to the movie.
Money, Dear Boy: David Cross makes it especially clear that he's in the movies for the money, noting that being in the first paid for a new house (he seems to have had enough with Chipwrecked though, which he called "literally, without question, the most unpleasant experience I've ever had in my professional life").
Initially, Ross Bagdasarian Jr. and Janice Karman portrayed Alvin, Simon and Theodore in the film, but were replaced at the studio's insistence with younger actors Justin Long, Matthew Gray Gubler and Jesse McCartney respectively.
It's not the first time Steve Vining provided the singing voice for Simon.
The Other Marty: Ross Bagdasarian and Janice Karman recorded all the lines for Alvin, Simon and Theodore.
According to Ross Bagdasarian Jr. (and Zachary Levi) the piano seen in the movie is the actual piano Ross Bagdasarian Sr. used to write and perform “The Chipmunk Song” as well as “The Witch Doctor” that launched the Chipmunks franchise.
Dave's house number is 1958, the year Ross Bagdasarian created the Chipmunks and released "Witch Doctor" and the "Chipmunk Song."