A worldlang is a type of international auxiliary language (or auxlang) that derives its roots, phonology, and possibly grammar from different language families in order to avoid perceived European bias (Eurocentrism). Traditional auxlangs tend to favor Euro-American languages and culture: Otto Jespersen admitted, "But I cannot object to my formula [the greatest facility to the greatest number] being taken to refer only to Europeans and those inhabitants of the other continents who are either of European extraction or whose culture is based on European civilization." 
Global neutrality was sometimes a claim of a-priori systems, but seldom of a-posteriori ones. Yet there are instances of the worldlang viewpoint in the twentieth century:
"Not one of these semi-constructed languages so much as considers the claims of Asia or Africa in spite of the millions of enlightened races speaking Russian, Chinese, Japanese, and Arabic. They are not ‘Interlanguages’ at all, but inter-European–and very partial at that." 
"Unlike its predecessors, designed exclusively, and admittedly, to meet the taste of Western Europe and the English-speaking peoples, Interglossa is for a world in which China, Japan, and eventually the peoples of Africa, will march in step with the U.S.S.R. and with western civilization." 
"Frater based on Latin and Greek roots of international currency is designed with due regard to needs of the Chinese, Japanese and other non-Aryan speech-communities. ... It is easy to learn whatever the mother tongue of the beginner may be."
"In connection with the constructed languages, some of the constructors avow that they are inspired by the principal of neutrality or all-inclusiveness, granting representation to all or most of the earth's languages..." 
Mario Pei tweaked a suggestion by the Rev. Theodore E. Leidenfrost that linguists "construct a Universal Grammar (and, presumably, vocabulary) on the basis of ten "representative" languages": Iraqi Arabic, Mandarin Chinese, English, Hindustani, Hungarian, Indonesian, Kpelle, Russian, Spanish, and Swahili. Pei suggested changing Kpelle to Hausa and adding Japanese and either Tamil or Telegu.
A parallel project Lojban has its root words phonologically based on Mandarin Chinese, Arabic, Hindi as well as English, Spanish and Russian.
Another, more distant, offshoot of Loglan is Ceqli, which has a theoretically open list of source languages.
Luis Sainz Lopez-Negrete's Lusane (1974) had a vocabulary "taken from more than a hundred of the more common languages spoken in the world," but because he did not list sources, the claim is difficult to verify.
Toki Pona is sometimes considered a worldlang despite the fact that it is not intended as an auxiliary language, because its phonology, morphology, and grammar are similar to those espoused by some worldlangers in projects such as Neo Patwa and Pandunia.
Rejection of Eurocentrism does not lead to uniformity. Some worldlangs, such as Ardano, draw from as many sources as possible, while others temper this by morphological (e.g., Ceqli and Sasxsek) or lexical (Neo Patwa) constraints. At the other end of the spectrum, Sambahsa-Mundialect is based on Indo-European, rather like Modern Indo-European, but has roots from other sprachbunds such as Arabic and Sinitic. Lingwa de Planeta (or Lidepla) restricts its primary sources to the ten or twelve most populous languages.
Intentions also vary. While most worldlangs, like most auxlangs, are meant for general use, Neo Patwa is intended solely as a contact language, and its root vocabulary and grammar are somewhat limited as a result. (This is similar to the disagreement between Jespersen, who apparently did not believe in the literary use of auxiliaries, and Dr. Zamenhof, whose translations were mostly literary.)
The ultimate result [of Interglossa's blend of Western vocabulary and roughly Chinese or pidgin grammar] would be that in trying to please everybody, no one would be pleased. This of course is the old stock argument of those who base their constructed tongues on a mixture of western languages: "Of what avail to try to please the Zulus by giving them six or ten words in the international tongue, which is all their numbers or importance would entitle them to? Let us rather try to make things easy for the majority of civilized people, who are in one fashion or another acquainted with western tongues.
Whether this philosophy of "to them that have shall be given" can continue to hold in a world in which the balance of power seems to be shifting is a difficult question to answer. Perhaps the ideal constructed language ought to be deliberately designed so as to please and flatter nobody, and make concessions to no one's existing language habits.
Pei (or rather Alexander Gode) also anticipated the clash between western projects such as Interlingua and worldlangs, using an argument similar to the one just mentioned: the western languages have considerable unity, based largely on the spread of Latin, French, Spanish, German, and English, whereas even Chinese and Japanese, despite much borrowing, have mutually incomprehensible vocabularies. A traditional, western auxlang can be somewhat immediately intelligible to its target audience; a worldlang typically will not be. Thus Gode took an Interlingua text that people knowing a western language could easily understand and substituted Asian words, resulting in a text few could understand at first glance.
- Otto Jespersen, An International Language, 1928
- Encyclopædia Britannica, vol 27, p 747, 1911 "Universal languages"
- Kenneth Searight, Sona (1935), p 12
- Lancelot Hogben, Interglossa (1943), p 15
- Mario Pei, One Language for the World, p 138
- Pham Xuan Thai, Frater (Lingua sistemfrater). The simplest International Language Ever Constructed., 1957, p 21
- Mario Pei, One Language for the World, p 95
- Mario Pei, One Language for the World, p 140
- Luis Sainz Lopez-Negrete, Falu Lusane (1976)
- Mario Pei, One Language for the World, p 139
- Mario Pei, One Language for the World, p 171-173
- Hogben, Lancelot. Interglossa. N.Y.: Penguin Books, 1943.
- Jesperson, Otto. An International Language. (1928)
- Lopez-Negrete, Luis Sainz. Falu Lusane. Mexico D.F.: Editores Asociados, S.A., 1976.
- Pei, Mario. One Language for the World. N.Y.: Devin-Adair, 1958.
- Pham Xuan Thai. Frater (Lingua sistemfrater). The simplest International Language Ever Constructed. TU-HAI Publishing-House, Saigon (Republic of Vietnam), 1957.
- Searight, Kenneth. Sona: an auxiliary neutral language. London: K. Paul, Trench, Trubner & Co., 1935. (Web version)