NEW YORK – Unsubstantiated rumours and outright falsehoods spread widely in immigrant communities before the US presidential election in 2020.

That is happening again in the run-up to 2022’s midterm elections, researchers say, but with an insidious twist: The social media accounts pushing misinformation are now targeting audiences in more languages on more topics and across more digital platforms, with scant resistance from social media companies.

In recent weeks, posts exaggerating the fallout from inflation have been aimed at Americans from Latin American countries that have been crippled by poor economic management. Conspiracy theories that spread in August about the IRS’s plans for a “shadow army” led mentions of “Ejército IRS” to surge alongside “IRS army”, its equivalent in English, according to the research group Zignal.

Misinformation swirling in Chinese on Twitter, YouTube and WeChat about mail-in ballots, school curricula and hate crimes “has dangerous implications” this year for Asian American voters, who are growing as a political force, according to the advocacy group Asian Americans Advancing Justice.

“There’s definitely a hyper-targeting of messaging,” said Mr Nick Nguyen, a co-founder of Viet Fact Check, a group that offers explanations about misinformation circulating among Vietnamese Americans. “This is where a lack of English-language fluency can make populations vulnerable.”

Viet Fact Check is among a growing number of groups trying to contextualise and debunk false online narratives in languages other than English.

Factchequeado, a six-month-old Spanish-language service, is examining inaccurate translations, manipulated images and misleadingly edited videos about the search of Mar-a-Lago and House Speaker Nancy Pelosi’s visit to Taiwan.

Desifacts, which focuses on South Asian American communities, began publishing explainers and clarifications about topics such as immigration and student debt relief in Hindi, Bengali and Tamil in February.

But the multilingual fact-checkers say they cannot keep pace with the deluge of falsehoods online. They have called on the big social media platforms, such as Facebook and YouTube, to do more for efforts in other languages as they would for misinformation in English.

“With mis- and disinformation in Spanish, we feel like we are fighting a giant,” said Tamoa Calzadilla, Factchequeado’s managing editor and the former head of Univision’s fact-checking operation. “It’s frustrating because we are trying to do something, and we need support from the platforms – we are doing our work, but Big Tech can do more.”

The social media companies said they moderated content or provided fact-checks in many languages: more than 70 languages for TikTok, and more than 60 for Meta, which owns Facebook. YouTube said it had more than 20,000 people reviewing and removing misinformation, including in languages such as Mandarin and Spanish; TikTok said it had thousands.

The companies declined to say how many employees were doing work in languages other than English.

TikTok has translated a midterms information hub on its app into more than 45 languages. Twitter has a similar elections centre available in English and Spanish, along with prompts that debunk and “pre-bunk” misinformation in different languages. Meta said that it had invested in initiatives such as Spanish fact-checking services on WhatsApp in preparation for the elections and that it would show voting-related notifications in both English and a second language based on users’ activity.

The companies also cited broader improvements.

Meta said its Spanish misinformation prediction models in the United States were now working on a par with its English-language models and had significantly increased the amount of Spanish content sent to fact-checkers for review. Twitter said its newly redesigned contextual labels, which are translated based on users’ language settings, had helped shrink engagement with misinformation. YouTube said information panels now appeared in different languages for certain search results and videos. It also highlights content from vetted non-English news sources based on users’ language settings and search queries, the company said.

But researchers worry about the effect of non-English misinformation on the coming vote, saying lies and rumours in other languages continue to seep through.