Pulling in over 100 billion searches per month, Google is bigger than ever. This consumer dependence on search engines as a means for information continues to keep search engine marketing (SEM) at the forefront of advertising, and the proportion of marketing spend put towards search marketing is only projected to grow as more and more businesses realize the importance of a strong internet presence.

But search as we know it is changing. OMI reports that 4 out of 5 consumers use smartphones to shop, and tablets are set to outsell PCs and laptops in 2013. So how will this affect the future of search engines?

Google has been investing in natural language processing (NLP), a branch of computer science that deals with the interpretation and generation of natural human language by computers. The technology aims to allow users to interact and converse naturally with computers, and Google is already beginning to release products using NLP.

Google Glass, Google’s much-hyped headset set to be released in 2014, will use natural language voice commands to allow users to take photos, videos, search, and more. In addition, last month Google introduced “conversational search” in Chrome browsers, a feature that uses NLP to interpret and audibly respond to users’ search queries.

Initial reviews reveal that the “conversational search” feature is far from perfect; elements of natural language such as slang, contextual references, and pronouns make NLP extremely complex. However, these product releases give us an idea of the direction Google envisions for search engines, and text-heavy search results pages won’t necessarily fit into that vision.

So what does that mean for search engine marketers? In the short term, it looks like keyword lists will need to be adjusted to be more compatible with natural language voice searches. This will mean more conversational keywords, including question and long-tail terms.

In the long run, it’s anyone’s guess. If conversational, voice-commanded search continues to grow, Google will eventually need to adapt its revenue model to be less dependent on pay-per-click ads. It will be interesting to see how and if search engine marketing fits into the picture.