  Large Language Models (LLMs) have recently emerged as a focal point of
research and application, driven by their unprecedented ability to understand
and generate text with human-like quality. Even more recently, LLMs have been
extended into multi-modal large language models (MM-LLMs) which extends their
capabilities to deal with image, video and audio information, in addition to
text. This opens up applications like text-to-video generation, image
captioning, text-to-speech, and more and is achieved either by retro-fitting an
LLM with multi-modal capabilities, or building a MM-LLM from scratch. This
paper provides an extensive review of the current state of those LLMs with
multi-modal capabilities as well as the very recent MM-LLMs. It covers the
historical development of LLMs especially the advances enabled by
transformer-based architectures like OpenAI's GPT series and Google's BERT, as
well as the role of attention mechanisms in enhancing model performance. The
paper includes coverage of the major and most important of the LLMs and MM-LLMs
and also covers the techniques of model tuning, including fine-tuning and
prompt engineering, which tailor pre-trained models to specific tasks or
domains. Ethical considerations and challenges, such as data bias and model
misuse, are also analysed to underscore the importance of responsible AI
development and deployment. Finally, we discuss the implications of open-source
versus proprietary models in AI research. Through this review, we provide
insights into the transformative potential of MM-LLMs in various applications.
