# High-Quality Data from Crowdsourcing towards the Creation of a Mexican Anti-Immigrant Speech Corpus
## 1 Introduction
### An Urgent Need to Build Resources for Mexican Anti-Immigrant Speech Analysis  
Mexico is a country of emigration, return migration, transit migration, and, to a lesser extent, immigration. This specificity is due to its geographical position as a \"bridge\" between the United States, the world's largest economy, and Latin America. The emigration experience, the sheer size of the Mexican dispora living in the United States, and the remittances that they send home have shaped a relatively empathetic public opinion and political discourse towards migrants [4].  
However, in the context of increasing restrictions on legal immigration to the United States and the worsening of socioeconomic, political, and security conditions in some Latin American countries, Mexico is becoming the main gateway for increasing clandestine migratory flows. Furthermore, since the beginning of 2018, the media coverage of clandestine transit migration in Mexico has increased considerably through the \"migrant caravan\" phenomenon, a form of mass mobility based on visibility.  
In the United States, illegal immigration has been a major national issue since the late 1990s and is one of the most polarizing factors in the political landscape [5]. In the United States, in 2017, [PERSON] started his presidential term with an ambitious program to address illegal immigration [6]. Faced with the impossibility of initiating a reform of the American immigration system, [PERSON]'s administration pressured Mexico, its primary trading partner, to stop the migratory flows passing through Mexican territory. Against all expectations, the Mexican government of [PERSON] executed with great zeal the injunctions of the American government, transforming Mexico into a vast migratory buffer zone [7].  
American pressure, the tightening of migration controls in Mexico, and the \"migrant caravans\" have made migration a \"spectacle\" that the Mexican public is forced to witness. According to the National Discrimination Survey (ENADIS) in 2017, only 13.0% of Mexicans surveyed were in favor of closing the border with Guatema and deporting migrants to their origin countries [8]. Two years later, a survey by the Reforma newspaper and the Washington Post indicated that this figure was over 50.0% [9]. The increasing hostility against migrants in Mexican public opinion is an emerging phenomenon that should be studied in the Mexican media, where discourse on migration is relayed, produced, and shared.  
The emergence of digital social networks and, more broadly, the growing digitization of media have accelerated and extended the dissemination of information. Moreover,anyone with access to Web 2.0 can now generate content, express their opinions, and react to content produced by others. The inherent distance in online interactions and the varying degrees of the echo-chamber effect and competition tend to create an online debate that is more polarized than its traditional counterparts, especially on controversial and widely discussed topics such as migration [10]. Recently, several scholars have studied the emergence of anti-immigrant speech in Mexican social media [2; 11; 12; 13]. As relevant as they are, these works only consider a small portion of the anti-immigrant discourse published on Mexican social networks, both in terms of the amount of data considered and the temporal coverage of the analysis. We still have very little visibility on this emerging phenomenon. We argue that it is paramount to build resources to systematically detect Mexican online anti-immigrant speech--specifically, to build a large corpus of such discourses for future analysis.