I'll start with the simple conclusion: no. Oh alright. Yes. Yes and no.

Somewhat fancifully, language is sometimes described as a tool, but that's not right either. It's more like a toolset, a massive and interlocking collection of tools that can be disassembled, reassembled, aggregated and combined to create many things, including more tools and more toolsets. The word 'and' might be a tool, but it has no meaning until combined with others into assemblies that perform tasks and it is those assemblies that are the technologies, not the language per se. In extreme cases, language does real work in changing the world directly: by making a performative utterance like "I do" the tool has become the technology that performs the action itself. In most cases, however, it is to do with communication and, I think more significantly, sense-making. Words can be used in an indefinitely large, almost certainly infinite number of ways to achieve a probably infinite range of results and effects. Language thus leads to an infinite range of technologies. More than the computer even, language is the universal technology. We can use language to manipulate ideas, create and transform concepts, design, explore, analyse and more in order to achieve some goal or goals. We can use language to manipulate language, and we often do. We can construct things in language and use those constructions to make other constructions. In language, a single word can express the abstraction of a billion ideas. Add a second word and we change that abstraction utterly. This is a mighty powerful toolset.

Like any technology and more than possibly any other, it takes a great deal of time to learn how to use a language at all, let alone well. It is in many ways the fundamental human invention, hugely more important and fundamental than fire, the wheel or the Internet. We can be human without fire, but to be human without language is barely conceivable, at least when viewed in the general sense, There are a few individual humans without language (babies for instance) but, were lack of language to become widespread, we would no longer be human.

Languages don't have to be verbal, of course: the advantages of verbal (and similarly sign) languages bring are also there to a greater or lesser extent in visual languages, musical languages, architectural languages and more. Words are not the only fruit by any means. However, the language of words is perhaps our oldest, most highly evolved and most flexible technological toolset and the richness of grammar and syntax it has evolved give it some large advantages over other languages we have invented. 

Language provides a toolset that, first and foremost, is not so much about communication as it is about thinking: it is an incredibly powerful, highly evolved technology to amplify and enhance thought. As we put thoughts into language symbols and connections we condense them and formalise them, allowing us to chain thoughts, hold more of them in our minds at once, build them into richer edifices. Just as writing is a thinking tool that lets us offload some of our cognition, allowing us to create longer and more elaborate chains of ideas that feed back and let us create new and enhanced ideas, language itself takes ideas, lets us abstract them and feed those abstractions back so that we can construct more thoughts, richer thoughts, more elaborate ideas. Learning a language might seem to be to do with communication but really, in learning to talk, we are learning to use a set of technologies that enable us to think. And from that ability we derive almost all other technologies. 

But, of course, the more obvious face of language is that of communication and here, too, that ability the technologies it enables give us, to symbolise, abstract and construct, also enables us to amplify and enhance the thinking of others: to act as a kind of hive mind in which the exchange of symbols enables the hive to build richer, deeper, more creative, more diverse thoughts, individually and collectively. Each new language act that we engage in with others is an opportunity to spread technologies, build ideas, learn, create, discover, enhance. It's a wonderful virtuous circle that leads to an ever expanding explosion of knowledge in our species as a whole even though we, as individuals, are likely getting dumber and are very likely dumber than some of our distant extinct cousins. It is not intelligence that makes us so 'successful' as a species: it is how we use technologies to amplify that intelligence.

Benjamin Franklin famously defined our species as man the toolmaker - homo faber as distinct from homo sapiens. It seems to me that our sapience is at least as determined by our toolmaking, most notably in the form of language, as our toolmaking is determined by our sapience. Probably more so.