No it’s not. You link to a news article that describes a master’s thesis (not a peer-reviewed study) that surveyed university students about their texting habits and then presented them with “new words.” (What is meant by “new words” is not clear.) It then found that students who said they texted a lot were less likely to accept the new words as legitimate than students who read a lot of print media. I’m not sure what’s being compared here because texting frequency and reading print media are two independent variables. (One can text a lot and read print media or vice versa.) Also, studies that rely on self-reported surveys are always suspect. One thing is clear, though: the study does not measure verbal ability.
As a rule, cite the study rather than the reporting of the study because most science journalism is crap. This article is a case in point. It does not adequately explain what the study actually did.
On the other hand there is this:
Chantal N. van Dijk, Merel van Witteloostuijn, Nada Vasić, Sergey Avrutin, and Elma Blom. ”The Influence of Texting Language on Grammar and Executive Functions in Primary School Children.” PlosOne, 31 March 2016, DOI:10.1371/journal.pone.0152409.
When sending text messages on their mobile phone to friends, children often use a special type of register, which is called textese. This register allows the omission of words and the use of textisms: instances of non-standard written language such as 4ever (forever). Previous studies have shown that textese has a positive effect on children’s literacy abilities. In addition, it is possible that children’s grammar system is affected by textese as well, as grammar rules are often transgressed in this register. Therefore, the main aim of this study was to investigate whether the use of textese influences children’s grammar performance, and whether this effect is specific to grammar or language in general. Additionally, studies have not yet investigated the influence of textese on children’s cognitive abilities. Consequently, the secondary aim of this study was to find out whether textese affects children’s executive functions. To investigate this, 55 children between 10 and 13 years old were
tested on a receptive vocabulary and grammar performance (sentence repetition) task and various tasks measuring executive functioning. In addition, text messages were elicited and the number of omissions and textisms in children’s messages were calculated. Regression analyses showed that omissions were a significant predictor of children’s grammar performance after various other variables were controlled for: the more words children omitted in their text messages, the better their performance on the grammar task. Although textisms correlated (marginally) significantly with vocabulary, grammar and selective attention scores and omissions marginally significantly with vocabulary scores, no other significant effects were obtained for measures of textese in the regression analyses: neither for the language outcomes, nor for the executive function tasks. Hence, our results show that textese is positively related to children’s grammar performance. On the other hand, use of textese does not affect—positively nor negatively—children’s executive functions.
There are dozens of other peer-reviewed studies that show the same thing. Texting is positively correlated with verbal ability. That is beyond dispute.